# What size to post photos on the internet?



## donnaj

Hello, I am not sure if I am in the right forum or not for asking this question. Sorry, I am new here.
I am wondering if someone can tell me what resolution is a good size for posting a photo, say, on facebook, so it isn't big enough for someone to right click and print a nice photo from it? Thank you very much.


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## KmH

Define 'a nice photo'.

If the photo is 600 pixels on the long side, they can get a print 6 inches wide at 100 pixels-per-inch (PPI), or a 12" wide photo at 50 PPI, or an 8" wide photo at 75 PPI.

This photo is 600 pixels by 400 pixels:


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## Derrel

KmH said:


> Define 'a nice photo'.
> 
> If the photo is 600 pixels on the long side, they can get a print 6 inches wide at 100 pixels-per-inch (PPI), or a 12" wide photo at 50 PPI, or an 8" wide photo at 75 PPI.
> 
> This photo is 600 pixels by 400 pixels:



THAT IS A BEAUTIFUL old-fashioned grocery store Keith!@!


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## Bossy

The highest most (if not all) computer screens can reproduce is 72ppi.  So there's no point in going higher than that. You can go lower, but your image quality can suffer, and regardless people will print it if they like it, even if its so pixelated it looks like the original mario.



​


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## The_Traveler

Bossy said:


> The highest most (if not all) computer screens can reproduce is 72dpi.



Perhaps in 1982


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## Bossy

The_Traveler said:


> Bossy said:
> 
> 
> 
> The highest most (if not all) computer screens can reproduce is 72dpi.
> 
> 
> 
> 
> Perhaps in 1982
Click to expand...


Did you get that from Google or did you actually have something productive to add to the conversation?
If I'm wrong, prove I'm wrong. I don't mind, I'm here to learn. I learned that from my professor in college, so if he's wrong I'm sure he'd want to know.​


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## The_Traveler

Just correcting a misstatement. 

for the OP

Most screens used today are at least xga which displays 1024 x 768 pixels regardless of their physical size. 

For display most forums have either a fixed maximum size or, as this one does, allows you to display pictures at your desired size.
Most people resize their posts to about 1000 wide x 700 high as that fits in the majority of display screens.
Since printing decent prints requires about 2 or 3 times the resolution of a typical screen, putting up prints this size makes them reasonably safe from being stolen and printed altho people can still redisplay them on a computer screen.


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## Bossy

The_Traveler said:


> Just correcting a misstatement.
> 
> for the OP
> 
> Most screens used today are at least xga which displays 1024 x 768 pixels regardless of their physical size.
> 
> For display most forums have either a fixed maximum size or, as this one does, allows you to display pictures at your desired size.
> Most people resize their posts to about 1000 wide x 700 high as that fits in the majority of display screens.
> Since printing decent prints requires about 2 or 3 times the resolution of a typical screen, putting up prints this size makes them reasonably safe from being stolen and printed altho people can still redisplay them on a computer screen.



Ok. But you can have an image at 1000x700 at 72ppi as well as 1000X700 at 300ppi. So what PPI are you saying to post at.​


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## KmH

Derrel said:


> KmH said:
> 
> 
> 
> Define 'a nice photo'.
> 
> If the photo is 600 pixels on the long side, they can get a print 6 inches wide at 100 pixels-per-inch (PPI), or a 12" wide photo at 50 PPI, or an 8" wide photo at 75 PPI.
> 
> This photo is 600 pixels by 400 pixels:
> 
> 
> 
> 
> 
> 
> 
> THAT IS A BEAUTIFUL old-fashioned grocery store Keith!@!
Click to expand...


Actually, it's an old-fashioned blacksmith shop - State Historical Society of Iowa


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## KmH

Bossy said:


> The highest most (if not all) computer screens can reproduce is 72ppi.  So there's no point in going higher than that. You can go lower, but your image quality can suffer, and regardless people will print it if they like it, even if its so pixelated it looks like the original mario.


PPI is meaningless for electronic display, so it can be set to any value and the image size will not change, unless it's automatically resized by a web sites software. Like I mentioned in my post, once copied the thief could change the PPI to any value.

I have a 22"(diagonal) main computer display. It is configured to display 1600x1200 pixels. The display has a horizontal dimension of 18.625".
1600 pixels divided by 18.625 inched = 86 PPI....Not 72 PPI.

I can change how many pixels my display shows, within limits, thus changing the PPI resolution to some other value.

In short, the only way to determine the resolution of a display is to measure the width or height of the display and divide by the pixel dimensions the display is set to.


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## Bossy

KmH said:


> Bossy said:
> 
> 
> 
> The highest most (if not all) computer screens can reproduce is 72ppi.  So there's no point in going higher than that. You can go lower, but your image quality can suffer, and regardless people will print it if they like it, even if its so pixelated it looks like the original mario.
> 
> 
> 
> PPI is meaningless for electronic display, so it can be set to any value and the image size will not change, unless it's automatically resized by a web sites software. Like I mentioned in my post, once copied the thief could change the PPI to any value.
> 
> I have a 22"(diagonal) main computer display. It is configured to display 1600x1200 pixels. The display has a horizontal dimension of 18.625".
> 1600 pixels divided by 18.625 inched = 86 PPI....Not 72 PPI.
> 
> I can change how many pixels my display shows, within limits, thus changing the PPI resolution to some other value.
> 
> In short, the only way to determine the resolution of a display is to measure the width or height of the display and divide by the pixel dimensions the display is set to.
Click to expand...


But if you change the ppi from say, 72 to 300, wouldn't that be upsizing and you'll have a not so great image? Or is a basic free program capable of reducing pixel size without loss?​


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## The_Traveler

Bossy said:


> But if you change the ppi from say, 72 to 300, wouldn't that be upsizing and you'll have a not so great image? Or is a basic free program capable of reducing pixel size without loss?



Don't think about PPI unless you are printing, then it is important to have  250-300 PPI to have a nicely resolved print.
PPI doesn't mean anything in web display.
Only think in terms of number of pixels on a side.


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## Derrel

KmH said:


> Derrel said:
> 
> 
> 
> 
> 
> KmH said:
> 
> 
> 
> Define 'a nice photo'.
> 
> If the photo is 600 pixels on the long side, they can get a print 6 inches wide at 100 pixels-per-inch (PPI), or a 12" wide photo at 50 PPI, or an 8" wide photo at 75 PPI.
> 
> This photo is 600 pixels by 400 pixels:
> 
> 
> 
> 
> 
> 
> 
> THAT IS A BEAUTIFUL old-fashioned grocery store Keith!@!
> 
> Click to expand...
> 
> 
> Actually, it's an old-fashioned blacksmith shop - State Historical Society of Iowa
Click to expand...


I think you missed the joke there...


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## Bossy

I missed the joke too :/​


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## Bossy

The_Traveler said:


> Bossy said:
> 
> 
> 
> But if you change the ppi from say, 72 to 300, wouldn't that be upsizing and you'll have a not so great image? Or is a basic free program capable of reducing pixel size without loss?
> 
> 
> 
> 
> Don't think about PPI unless you are printing, then it is important to have  250-300 PPI to have a nicely resolved print.
> PPI doesn't men anything in web display.
> Only think in terms of number of pixels on a side.
Click to expand...


What am I looking at when I see pics on the internet that are pixelly? Does that not have to do with re/ppi? ​


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## The_Traveler

Bossy said:


> The_Traveler said:
> 
> 
> 
> 
> 
> Bossy said:
> 
> 
> 
> But if you change the ppi from say, 72 to 300, wouldn't that be upsizing and you'll have a not so great image? Or is a basic free program capable of reducing pixel size without loss?
> 
> 
> 
> 
> Don't think about PPI unless you are printing, then it is important to have  250-300 PPI to have a nicely resolved print.
> PPI doesn't men anything in web display.
> Only think in terms of number of pixels on a side.
> 
> Click to expand...
> 
> 
> What am I looking at when I see pics on the internet that are pixelly? Does that not have to do with re/ppi?
Click to expand...


Hard to tell because I don't know what pixelly means.
Point to a picture.


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## Chann

To interject, the display screen DPI is set by your computer system and is not fluid. My laptop has two presets.

96 dpi or 120 dpi. I have it set to 96 dpi. 

If I create a 4x3 image in PSP (I do not use PP) and specify 96 dpi, when viewing the image at 100%, it will physically measure on the screen at 4x3.  If I were to resize it to 120 dpi, it will physically measure at 5x3.75 on the screen. I would have to set my monitor to 120 to have it measure 4x3 again. 

 Therefore, for viewing online only, you do not need any more than what you monitor is set to. 72 dpi was very common on CRT monitors but LCD are typically a higher resolution.  Then, the dimensions that you set your image to will be the size displayed ( when viewed 100% full size). 

i never worry about ppi. If i am printing I use 300 dpi or more and it always looks fine. I print on an Epson Artisan 730.  This works for my needs.


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## KmH

Nope. The pixel dimensions are all that matter for electronic display.

The value the PPI needs to be is dependent on viewing distance and the image quality of the photo .

Desk size prints generally need to be at or above about 180 PPI. A desk size photo with very good image quality may print well at 100 PPI.

Here is the photo I posted above, still at 600x400 pixels, but I changed the PPI value to 1 PPI:


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## Bossy

Wow KmH! So basically, any image you pull off the net, you can print at what dimensions is is without loss. But its when you start to blow it up you get pixelated right?​


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## KmH

Pixels-per-inch (ppi) and dots-per-inch (dpi) are not interchangable terms. It takes many dots to render a single image pixel.

DPI is a description of output device resolution, like imkjet printers. PPI is a description of digital input device resolution, like digital photos or scanners.

Unfortunately, many (including many scanner manufacturers and other professionals) pander to the ignorance of most consumers and routinely use the term dpi incorrectly, which isn't really helpful.

I don't know about PSP, but Photoshop always refers to input resolution as *pixels* per inch or *pixels* per centimeter.

Typical desktop inkjet printers output (dots, not pixels) at resolutions of about 360 dpi to 2880 dpi. 360 dpi would be used for speedy, low quality printing and ink saving, while 2880 dpi would take longer, use more ink, and produce a higher quality print, even if the image ppi was set to a low value like 100 ppi. Some inkjet printers print at even higher resolutions and those prints are honored with the word Giclée, a neologism coined in 1991 by a printmaker at Nash Editions.


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## KmH

Bossy said:


> Wow KmH! So basically, any image you pull off the net, you can print at what dimensions is is without loss. But its when you start to blow it up you get pixelated right?


No.

You're not alone. Lots of people can't follow the basic math, or the logic.

If you print that 600x400 image then the PPI value definately matters, but the PPI can be changed between the time the photo is copied and when it is printed.

At 300 PPI, each of those 600 pixels would be 1/2 inch square, and clearly visible *as a print*.


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## Bossy

Agh ok. I'm going to sit on this for awhile, I thought I understood it but now I'm pretty sure I really have no idea  I just set mine as 300 and send out to print >.< So, I'll be back, or might start another thread, or might just google myself to death, because its something thats good to know. ​


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## Bossy

Thanks for taking the time to respond, btw  I know it isn't really my thread hah.​


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## fotorobot

Thats really nice picture


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