I see that this question is quite old, and no one seems to have answered it, so I hope I can help.
I use Confluence Cloud (formerly Confluence Ondemand), and the way to add a title is that instead of clicking on Instant Camera under the effects, I click on Title. From there I enter the text I want in the title field. When you save your changes, a title should appear after you hover over the image.
Olivia gajadhar
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