Are uploaded images altered in any manner when they are uploaded and sent to DropBox through our form?

- Images dont get crunched or re-sized on the process, right? We need printing quality

No.

All of the files that are uploaded over your form are passed to you as they are, there are no modifications done on our side - at least not unless you explicitly set something to be done, which is allowed in only some widgets like: Ink File Picker, but the upload field or Image Upload Preview widget will not - nor have such settings.