Hello and Greetings.
I would like to know what is the best size and resolution for submitting stock image's? I have been setting my image's at 2400x3000 @ 300 DPI for selling on Red Bubble and Fine Art America. Is this a good size and what else is should I look for when submitting images to stock company's?

I had the same problem with Veers but my last upload to them was 3000x2400 @ 300dpi,figure this was a good size but I was wrong,they where rejected for pixelation. Was this a good size or not?