As stated in the question, Which is appropriate to use 'indicate' or 'show'?
The photos indicating the area are enclosed herewith.
The photos showing the area are enclosed herewith.
Apart from this, do you think we can remove "the" before "photos"?
Any other example will be appreciated.
Indicate doesn't mean showing something by pointing at it. it rather means to show that something is true by providing information about it. so I think we can't use indicate in this case. For the "the", dropping it will be fine unless "the photos" has been referred to before.
"Showing" is more appropriate in this context.
As for the "the", it should only be removed if you have not previously mentioned the photos in the letter.
The photos indicating the area are enclosed herewith.
First off, I think the use of herewith followed by enclosed is outdated and unnecessary, though its use with enclosed is common in India and Pakistan in business correspondence.
Second, as the verb "indicate" can also be used in the sense of "show", you can use either.
Third, you are talking about specific photos, mentioned or known before, for which you are using relative defining clause "indicating the area", I don't think it's possible to delete the definite article before photos.
