How to insert many pictures into a frame on each Impress slide via Insert > Media > Photo Album

Insert > Media > Photo Album is very useful for inserting many pictures into slides - a picture to a slide.
It fills each slide with a picture, often leaving no room for a caption.

Insert > Media > Photo Album has a checkbox option to include a caption are on each slide, however that is semi-transparent and partly blocks the bottom part of pictures.

A. How can such automatically created caption areas be defined for all slides to be totally transparent, invisible background so only the caption text shows? The text would still cover part of the pictures.

B. Is there a way to define a master slide with two frames: one for the photos and on the bottom a text box for captions and have Insert > Media > Photo Album insert pictures only within the photos frame?

C. If option “B” is not possible then is there a way to define a master slide with two frames as in “B” and after Insert > Media > Photo Album inserts pictures taking up much of the space of each slide resize each inserted pictures in one operation to be reduced by a certain percent and top aligned?

PARTIAL WORKAROUND: If I open a LibreOffice presentation in OpenOffice I can click on the text box, then on Area. It has a Transparence tab. Setting transparency to 100% makes the text box background transparent. Of course the text still covers the picture. I succeeded doing the same in LibreOffice, but in general it is difficult to get to see the Area option.

The workaround has to be repeated for every slide and not done once as default for all slides.

@LDP - Good idea. I regularly use your partial workaround. It’s a bit cumbersome, What you can do is to modify the Title text in the master slide and then Clear Direct Formatting when editing the single slides.
Probably you start a feature request at bugzilla.

Thank you.
Tried View > Master Slide > Edit Style, set Transparency to 100% and saved.
Had no visual effect on slides and when I repeated Tried View > Master Slide > Edit Style and Transparence was still 0%.
Do you know how I can set transparency globally to 100% via the Master Slide?

Do you know how I can set transparency globally to 100% via the Master Slide?

I tried to alter the Title text style and the Title text itself, but something weird opposed my endeavors.

The captions on inserted Photo Albums is hella confusing. I think it uses the Title from the Default master slide (even if you change the slide’s Master Slide to some other slide). If you go to Master Slide view, and right-click in the “Click to edit the title text format” box and choose Edit Style… , then you can change Area to some color and Transparency to some amount. Then it seems photo albums will use these settings.

However, it seems the next pictures you import will go back to white on black. I think photo albums use the title format from the Default master slide, but add their own direct white (or Automatic?) on black Area formatting. You may have to select the text of the caption and choose Format > Clear Direct Formatting.