When you open Pixly, click on right top button (the brown-red and white square)
.png files are accepted too
When you add the Quake2 pal, it can be renamed the way you wanted.
From a spaceship toy, you can get a squeaky sound when you rotate the top, and you can use the sound, for a door or a door with chains.
Almost all sounds are made manually
Door with chains example :
Google Drive :
squeaky sound2