Editable file formats

[Pandora]

I'm an old Corel Draw/Paint and PsP user who's just trying to get the hang of this hybrid raster/vector medium. I'm finding so many barriers but here's one that's really baffling me. I can't find a way to save files and be able to edit them later. Whatever format I choose, the files are garbled when I re-open them. I can see why there might be issues using competitor's file formats like EPS or PSD, but why isn't there a native format like, for example, the old .cdr?

[markkus]

The native format is .PSPIMAGE.

[Jean-Luc]

The .pspimage format is PSP's proprietary format. It retains layers, settings, etc.
There is no compatibility between .cdr files and .pspimage files.
If you are a CorelDraw user, continue to use it for the vector and use PSP for the raster.