I have discovered a bit of an annoyance when pasting an image into a page where the image doesn't have a specific name of its own

e.g. you might use a snipping tool or select an image from some other document and copy it, then go to the Confluence page in edit mode and paste the image in.

Confluence treats that as an attachment but as it has no specific name so logically Confluence automatically assigns a name - that name is based on date and time stamp e.g. it would assign a name to the attachment like

image2019-7-13 8:37:43.png

the problem is the colons in the time stamp portion.  

if you later want to download all attachments, the zip file is created ok and will download

But when you open the zip file, WINZIP pops up a message that it is an invalid filename.  The message suggest that you should still be able to unzip the file but I have failed to be able to do so and the file appears empty.

So it would be extremely helpful if Confluence used something other than colons in the auto-assigned filename ... even just stripping out the colons in the time stamp would help as I currently have to work through dozens of attachments on hundreds of pages and manually remove the colons in the file via the Properties option for each attachment.

It would be even more helpful if the auto file name process included reference to the User who created it, rather than just "image"

Given Confluence has its own interpretation of the meaning of a colon in a page/file name, it would seem logical not to allow its use when autonaming image attachments being pasted into a page.