File Formats and Layering

File formats and layering
Use whatever software you are comfortable with. Nobody needs Photoshop.
Finished PNG — required
Full quality/lossless, transparent where appropriate, RGB/sRGB, and keep a high-resolution master.
Original layered source — required when applicable
Submit the native layered file you actually worked in: 
.kra, 
.clip, 
.xcf, 
.procreate, 
.afdesign, 
.afphoto, 
.psd, or whatever your software uses.
Open/interchange copy — optional
OpenRaster 
.ora is useful when supported. A layered TIFF or PSD export is welcome as an extra but is not required.
Vector art
For logos, icons, buttons and UI, include 
.svg when possible.
Keep useful parts on sensible layers and work larger than the tiny legacy asset when practical. Engineering can handle SWF/game integration.