Yes, the spraycan is not controlling your pixels and therefore frowned upon in the PJ gallery.
It is for this reason that its been waiting to be added to your gallery. Since, it hadn't been brought up yet as I expected, then please alter that. Remake the sky or dither it in a more acceptable manner. The highlights on the pile is a bit oekaki-ish too, so spend a little time with that too.

The bigger the canvas the more careful the pixel placements are called for : |

Yep, it is. Is that problem? I know  it isn't correct way to do that  but well... I'm working on picture, thanks to everybody for their critics.

Just one question.
Is the sky drawn/colored using the spraycan brushes?

The colors are great, I think you should have worked on shape and shading more.

Have something going on in the upper right hand side of the screen. Maybe have the sun seeping through the smoky sky. Add a few more birds to the sky.

This is a really awesome piece of art though. good job

try reducing the saturation, right now the background is almost blinding...

You should make the hanging bodies look a little more human and less like dummies