I played with a table layout, but one-column looked sparse, and two-column wouldn’t fit on a mobile screen.

However just dropping the photos in worked fine, if the photos were centred.

Then when I added some text – lorem ipsum paragraphs – I found that both text and photos fitted neatly on the mobile, as well as on iPad. And the portrait format on the mobile even formatted neatly when some of the photos were left or right aligned!

(See http://www.paulhulbert.org/swehs/bath-test-photos-3/ )

The vertical photos were resized to custom width 300.

The photos had Captions and Alt Text generated from a spreadsheet, e.g. SWEHS_5.2.021.jpg – Date 1920 – Customer record.

Note that the photos were renamed before being uploaded to avoid the problem of the space in the name – not sure that this was strictly necessary. Try again in the next trail.

Once I have a procedure, need to try a nearly-blank installation of WordPress with say 1000 photos loaded, and then whether I can then run a backup properly.