Well, I'll try and be more clear:
• If you want XYplorer to be able to edit images like FastStone Viewer, XnView, then it won't, whatever the image format.
• If you want XYplorer to provide for PSDs, EXRs, etc. the same "full image support" that it does with jpegs, that is: Thumbnails, MouseDownBlowUp, Pane Preview, Floating Preview, FullScreen Preview, etc. then codecs are what you need.
Codecs for pics are no more "
junk" than codecs for videos.
- If you were an average user, Windows support of jpeg, gif, etc. would be sufficient.
- But as soon as you start using dedicated image formats, be it RAWs, HighDefinitionRange or 3D related, then you can't expect them to just work out of the box.
Those formats are far too many, and updated far too often -e.g. especially camera RAWs- that only dedicated image editors or codecs can keep up with them!
So Windows will certainly never try nor be able to handle them itself, and XY isn't an image editor.

Same as you probably installed QuickTime and Flash
(and presumably KLite or one of its brethren) even if you didn't want to, you'll need a codec pack for your pics!