but am running into issues getting the images cropped to a size the wiki allows.
Is your issue file size or dimensions?
Ideally neither causes a problem. You upload a pic at max quality/resolution. Then reference that file in a wiki page, which will automatically resize to your desired (or, wiki defaults) dimensions.
The format to reference an image is
[[File:[I]filename.extension[/I]|[I]options[/I]|[I]caption[/I]]]
- the various options are described
here. In most cases, I specify options of "thumb" and "300px" and the pic is perfect.
For example, on
this wiki page the top right pic was added with this code
Wiki:
[[File:GSeries Family.png|thumb|right]]
which auto-resizes the original pic to the size displayed. But click the image to see the original. You'll see a big image, and all resizing is handled by the wiki code, saving us humans the work.