The only one I have actually installed is PagePlus X6, which is probably usable for what I had in mind. However, I was thinking of something smaller and simpler.
PPX6 would probably work for you if your intended "final destination" was a printed page -- but (a) I assumed you were more screen-focussed and (b) I was trying to find a free solution that I'd be at least reasonably happy to use myself.
Serif kit -- despite their marketing tactics and their occasionally overpushy salespeople -- is mostly pretty good. (You can always opt out of the emails!)
IainB's suggestion of OneNote looks good, but I'm not sure it's an appropriate solution to the problem if it's the only likely use you have for it and if you don't already have an Office license.
If you already have a PhotoPlus license for pretty much any version at all, you can use it to create a new, blank image then drag in images from Explorer or ScreenshotCaptor or whatever; each dropped image becomes a layer that you can manipulate independently of the others, with each layer being automatically named for the image's filename. (PhotoPlus also has screen capture capabilities, if you're in reductionist mode, although ScreenshotCaptor has elbowed everything else I've
ever used for such purposes out of the way!) At any stage you can choose to merge all the visible layers into a single image, or you can leave the layers in place and export the visible layers into a normal graphic with the usual range of output formats.Photofiltre
might also be worth a look. It also optionally works with layers but it also has quite a nice facility (Assemble) that'll take the image on the clipboard and add it to the top, bottom, left or right of the current image. (v7 is free for private use.) In contrast to PhotoPlus, images dropped onto Photofiltre are handled separately so you would probably do the resize, then copy to clipboard, switch to the primary image then use the Assemble function.
Another possibility along similar lines is Fotografix
. Smaller and less feature-rich but also layer-aware and the transform tool (for resizing layers) is easy to use (remember to shift-drag to constrain the image to its original proportions -- same as Serif in that respect.)