How do I down-scale a photo inside a rectangle?

I design & create medieval card stock models in 1:87 scale. I've been using Affinity products, but want to switch to Xara. I normally use 2" high graphics at assorted widths to simulate walls. In Xara, when I import a picture of stone (for example) and then resize it to 2" high, the entire picture resizes, including the outline. I need just the picture to resize (not the borders of the photo), because the scale of the stone has to look realistic for its size.
In the Affinity software, first I create an outlined rectangle the size I want. Then I load a photo or texture into the rectangle. At that point I can now resize the photo/texture to the scale I want inside the rectangle without affecting the size of the rectangle itself. But in Xara Designer Pro, the different options to resize affect both the photo and the rectangle. Even that control near the upper-right corner of the rectangle only works to resize larger, not smaller (like I need). And of course, the handles on the top/bottom/left/right sides of the rectangle simply crop the photo.
If I cannot overcome this problem, then my use of Xara DP will not go beyond the trial date. I would appreciate any help that can be offered.

Select the photo with the Fill Tool (F5).

You will see a pair of arrows. Click on the small box at either end of the arrows to select them.

Then use the arrow keys to enlarge or reduce the fill.

Use Shift + the arrow key to enlarge or reduce at a greater amount. Use the Alt key + arrow to enlarge or reduce in 1 pixel increments.

The ends of the arrows can also be dragged to rotate the fill.

Wow! Thank you!! That's exactly what I needed. I'd searched the Help file under words like resize, resizing, adjust, etc, but found nothing. I'd never have thought of looking under Fills. I truly appreciate your help with this, and now Xara DP is back on my list for purchase.:)

technically in xara software, photos are actually bitmap fills in a vector container and the photo tools work directly on the fill

when you click on a photo with the fill tool selected you will see on the infobar dropdown that fill type is 'bitmap'

in otherwords, in xara, the photo is always preloaded into a rectangle; xara does not have an object type that is stand-alone bitmap