How can I crop an image? Texture/photo.

I’m just starting in UE4, so forgive the question if it’s too easy.
I drag an image I like into UE4. It shows up on the Content Browser.
I drag that onto an object in my scene. A box. It converts it to a Material. I can see the ball shape.

If I double click on either the Texture, or the Material, I can see the image of the 2 dogs I dragged in.
I want to crop out one dog, and I want to make sure the proportions stay as they should be, and not stretch to fit the box, they will be attached to.
I just want to create a simple room, with a photo on the wall, but I want the photo frame to stay the shape I have it, not adjust the frame to stretch the photo to the proper shape.
Any ideas?

It is possible with UVs, but I think it’s easier to fix the image before you import it.