Question / Help Question About Showing Images/Slideshow in OBS Studio

[jacobmercy]

I'm planning on reading a comic on stream, but I'd prefer to not show the whole thing. The issue is that sometimes I might want to show a splash page, or just a panel. The shapes and sizes of these would vary a lot.
Ideally, I'd like to be able to "clip" whatever I happen to be reading and just have the clip automatically show up nicely positioned and aligned, but I can't figure out an efficient way to do this on the fly. The best way I can figure out to do this so far is:

1. Create an image source.
2. Use the snipping tool to select an image.
3. Save the image.

The problem with this is that since the panels can be different heights and widths, I'm constantly having to adjust the transformations in OBS. I've also tried making multiple sources (one for a single rectangular panel, one for a wide panel) but then I have to start using multiple filenames and keep track of them, which I'd prefer to avoid.
Anybody have any good ideas or plug-ins to recommend? I'm kind of stumped.