DePo Masthead (below comment box)
For the rest, you can manually create such navigation tabs (if you don’t mind the awful chore it is):
1. For a text link, e.g. “Next”, the code would be:
For a thumbnail link instead of the text tab, the code would be:
(The height number is a suggestion – you can change it. The URL of an attachment page is the post URL plus the image name as it shows up in the image URL, without the “.jpg” part, folllowed by a slash.)
2. You create these links, then create the following table code and paste it in the description box of the images:
For the first and last images you can have a link with the appropriate text tab instead of “Previous” or “Next” (e.g. “Back to post”), or you can leave that part of the table code (the part shown in capitals) empty, if you want nothing instead.
The “100%” shown above is suitable for fixed-width themes and large images that will occupy the whole of the available post or page width. For flexible-width themes and/or smaller images, the first line of the above code should be:
Where “number” is the width of the image (or around 10 larger than that, if the theme creates borders or frames around images).
Example here. [Update 26/10: messed up now that attachment pages automatically include navigation thumbnails.]
For a simpler alternative you can omit the table – just write this in the description boxes:
This way you get both tabs aligned left, the one below the other. Less work to do; but less elegant.
Easier alternative: forget the gallery feature altogether, upload and insert independent images, and use page splits after each image (the “nextpage” tag – see here). This way you’ll get a series of pages with a series of number links below them. Example here (created after her question / my suggestion in the forum).