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Intro: I'm not a GD, but bear with me. I've been doing digital illustrations for a while and never had an issue with posting them anywhere, until this year. I keep getting all my illustrations sort of blurred/pixelated every time I upload them to most social medias. I use Illustrator CC. Most of the time I create my work on a CMYK file (just in case if I ever want it to print it), 300 ppi, align to pixel grid and then export it on RGB. Mostly on square format (20x20cms, I changed it to 1200px x 1200px as someone suggested those measurments me for fb) This is driving me nuts. Believe me I've tried everything (save for web, save for microsoft office, jpg, png, different sizes and resolutions according to fb, tw, pinterest...) The only place they look great are tumblr or behance, since they don't compress anything, so far. I'm ready to try everything one more time, for the sake of my images looking sharp.
Here's an example of what I'm suffering. Left one is the fb uploaded version. Right one the original, how it should look.
Help a girl out! Thanks