PPI question

I didn’t know exactly where to put this question so moderators please move it if need be. I have an image I am using as a cover photo for a facebook page. The pixel dimensions are 851x315 as facebook requests. When I export the file from illustrator as 72PPI it is blurry, when I export it as 300PPI it isn’t. Both files are exported as a PNG and are the same pixel dimensions. Can someone please explain this?


Looks blurry where?
Are you sure your pixel dimensions are 851 x 315?

So when you make an image 300ppi - it will then be 3546x1313
As it increases the amount of pixels per inch.

How does it look on Facebook?

My advice would be to open the image in Photoshop - that is open the AI file in Photoshop
Then set the size to 851 x 315 @ 72 ppi

Then try that.

We could explain it if we knew more of what you’re doing. There’s no visual difference between an 851 x 315-pixel image at 72ppi or at a million ppi. It’s still the same image with the same number of pixels.

My best guess is that you’re resampling/interpolating the image at some point in whatever software you’re using and inadvertently adding or subtracting pixels — either that or introducing different levels of jpeg compression to the images before uploading them.