my paintings doesn't look in good quallity in C2

Hi everyone. i made png paintings with gimp. in C2 they look in bad quallity. its look better just when i change their size to smaller.

how to make that the paintings will look good in their orginal size. (the window size is 1280x720), (the layout size is 2560, 1440) ?

You haven't given us any details with which to work, but the most likely culprits are you have changed their size (stretched) them on the layout, you are scaling the game window (thus stretching it inadvertantly), or you aren't snapping to any sort of grid so the position might be on a subpixels (make sure the position of the object didn't have and decimals). Beyond those, there's no way to guess, so possibly provide a capx so we can quickly see what's up.

What ive done is make the images in a bigger size when im creating them, pretty much i set my canvas at the size of the window size i will use in C2, the images come up looking as in my editor, just b careful with memory