Yes I used to experience pixelated photos but that was a while ago and it hasn't happened to me since. For reference I use Mac OS for desktop and iPhone and iPad. Here's my shortcut, if I can find a stock image of my item for sale, I use that. Let's face it once cleaned up even my own photo looks like stock image anyway. The second short cut is my photo showing dust bag, tags, accessories with the item always goes as photo #2, never the cover photo to avoid the problems you've been having which is getting cropped, photoshopped etc. Tradesy doesn't clean beyond the cover photo so best to save pics with your own identifiers after the cover.
I should have been more clear earlier that although I use the desktop version of Tradesy I'm still on iPhone or iPad. I typically only edit listings or create drafts on my laptop. I find it more seamless to upload photos using iPhone or iPad, for some reason photos don't sync on my laptop as quickly as I'd need them. The photos take on iPhone maintain the same size and resolution when uploaded via desktop Tradesy on iPhone.
Crazy I know of how much workaround I have to create to put up a decent listing but such is life lol. Another quirk I have to deal with is uploading pics via desktop on iPhone means I have to do one pic at a time if I want the order to appear correctly cuz guess what on iPhone I don't have the ability to move pics around with my finger!! In a nutshell I constantly juggle between app and desktop on my iPhone to finish a listing, until recently I could stay within the app from start to publish before photo sizing got messed up. Maybe things will go back to normal again, sigh... This is what happens when you have developers who are not product users, they rarely are according to my startup friends. They can code until the cows come home but I bet you anything they've never tried to search for a
Coach bag or create a listing and successfully sold it. In order words they can't talk and walk in high heels at the same time.