Looks good on computer but pixelated on phone?

@katielp  I agree with @Trevor.Dennis  - set the image size to the phone screen resolution (don't worry about PPI) and try that on the phone. How its delivered to the phone will perhaps affect the result too, some online apps will resample.

I hope this helps
neil barstow, colourmanagement net - adobe forum volunteer - co-author: 'getting colour right'
google me "neil barstow colourmanagement" for lots of free articles on colour management

Hi Katie.  PPI is only relevent to prints.  It tells the printer how densly, or thinly, to spread the pixels on the printed page.  For any sort of on screen use of an image, it's the pixel dimension that counts.  If your monitor has a 1920 X 1080 resolution, then that's the optimal image size to display on that screen.  A lot of phones have very high resolution for their size, so a higher pixel size would look the best, but that 1080P res image is still going to look amazing on the small screen.

So you need to know the image guidelines for the phone app your trading cards will be displayed on, and use that information when creating them on your PC.   If your trading cards are a graphic design rather than a photograph, then that will often work well at lower resolutions.