BACKPORT - As a CMS user, I want my images to be renamed in a such a way that the extension is kept, so that all browsers properly request and render the image.

Images are now currently renamed in the same way as other files. This means that when I have f.ex "mypicture.jpg", the copy will be called "mypicture.jpg (copy)". Not all browers like this and it looks strange to the visitor.
It'd be nicer if the CMS would create a copy with the name "mypicture-1.jpg" instead. And the next one being "mypicture-2.jpg".
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Junaid - Retaining the extension is kept but the logic works as described below (not above):
When CMS users copies image (nice hippo shot.jpg), the new image name will have " (copy)" before extension. I.e "nice hippo shot.jpg" will be named as "nice hippo shot (copy).jpg". This way extension is retained.