On any page with a picture or placeholder, hold your mouse pointer over the picture (image) or placeholder. Use any of these buttons or controls:
Click
(Change Image) to open the Image Toolbox.
Use it to choose an image, crop it and specify metadata.
For an overview of the various controls, see Picture.
When you use Paste Image, but the image on the computer clipboard does not have a name, Bloom will name the files Image, Image1, Image2 and so on. If it already has a name, then Bloom keeps that name.
You see those names when you use the command Show in File Explorer.