Scribus lets you crop images easily by choosing "properties" > "image" > "free scaling". After cropping, you can even move the image around inside the frame by double clicking on the image and then dragging it. I love this functionality. Very useful. BUT after I've done this, I want to enlarge the image and the frame easily.
The best thing I've come up with is: open transform dialog to enter an exact scaling amount and scale the image frame, then do some math and appropriately scale the image by the same proportion, then re-position the image within the frame.
I'd love to find a quicker way to do this. Very cumbersome at the moment.
Note that I'm not looking for the "Scale image to frame" functionality because that doesn't let me crop the image within Scribus. Also note that I don't want to crop the source image because I want to be able to re-adjust it later if necessary.