I should have also said that in FF 'Paste' remains greyed out.

Right click, then select Copy Image.

Or Save Image As . . .

As I thought I'd explained, if I right-click on 'copy image', when I navigate to the intended repository in FF the 'paste' option is greyed out, though the same procedure works perfectly well in IE.

Using the 'Save Image as' option is (literally) a no-go, too, I'm afraid; when I try this, FF just goes into 'not responding' mode.

You can try to drag the image instead to see if that works.

Yes,thank you; this worked well enough to meet my immediate needs, but still in rather an odd way.

I first tried dragging an image from a table of images produced by an eBay search. I dragged the first image onto the desktop without difficulty, but when I tried to drag a second image in the same way it replaced the first image, rather than being shown alongside it. Dragging a third image caused it to replace the second. In other words, I was only being permitted to drag one image from this site.

I then tried the same thing on images produced from a Google images search.This time I could drag several images without difficulty, except that each one displayed on the desktop as a Firefox icon, rather than as a thumbnail of the original image, as had been the case in the first example.

I do wish I could make FF do as IE does!

Incidentally, I've found another case of FF failing to do what IE can do, but I'll keep that in reserve until we've got a bit further with this one.

Did the image get saved as a file, or a background image? If as a file, it might be that they all had the same file name. Try to move ONE picture. After the file is created, change it's name. Then do the same for the others.