Update the title for the images/EPS on maps gallery example

[core-man]

Description of proposed changes

Update the title for the images/EPS on maps gallery example (Originally posted in #995 (comment))

By the way, shall we rename this gallery to something like Images or EPS files on figures since we can put them on any figure instead of only a map, right?

Sounds good. Actually, Figure.image() can recognize most image formats (png, jpg, eps, pdf et al.) via GDAL. So I think we could just say "Put images on figures" or similar.

A tiny improvement is also added for the comment of position argument.

Related to #983 and #996.

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