Oh, I didn't know about the voting system. And also didn't know about dithering on small sprites. Hope that this pic will pass, because I really like it and was drawing it for a long time. Anyway thanks for answering and helping to figure out what could be a problem

Resubmitting resets all the votes you gained, so it can actually result in your submissions taking longer. If people notice that you resubmitted, it might also make them suspicious about what the problem might've been, and they might be more reluctant to vote "yes" ):

This one might be getting some "no" votes because it's a bit noisy (dithering on small sprites tends to read as noise), which would slow it down. In addition, the mods try to pace the submissions they approve so that everyone gets some time on the front page, so maybe you were just very lucky before.

I thought that it waiting for approval too long and resubmitting will help. My another two artworks was approved pretty quick althrough I submit them after submitting this pic, so I found it kinda weird 

Why did you resubmit this?