I recently did something in LibreOffice Writer that I think is similar to what you are trying to do with positioning things. I was creating a PDF form for entry of account details. For all our bank accounts, investment accounts, etc. I wanted to document where they were and how to access them for my kids. We currently have this in a spreadsheet, but I wanted to try creating PDF's that would both be stored on a USB drive and printed out to be inserted in a paper notebook in a fire resistant lockbox (that actually would be kept in a fire resistant safe, for double fire protection). I got a little carried away and created drop-down boxes that are pre-populated with choices for the form. e.g., "Account Phone #" We only have so many phones that we could specify for an account (our landline and my wife's and my cellphones), so instead of typing that in you can just choose it from the drop-down. The drop-down also lets you manually enter a different phone number, if the provided choices are not to your liking. Anyway, that's just fluff to make the form fancy.
The positioning I do in the form below is via tables. Tables within tables, within other tables, to be more specific. Lots of nested tables.
But some positioning requires more than that (and that's the part I think you would be interested in). Note that I have boxes drawn around input elements that should be grouped together. Like the one near the top labeled "Account Details" (circled in red). The box is simple - just a table cell with a border. But overlaying that text "Account Details" over the box took a bit more fancy positioning. To do that I created a floating "frame" that in turn contained a text box that contained the text. I anchored that frame to the first cell of the table (the one with the border). And then I went into "frame properties" and twiddled the position variables. This twiddling was trial and error to come up with the vertical and horizontal offset I needed to move the text up and over so that it overlaid the border in a pleasing manner. I'm thinking that you want to do similar positioning with images. You could use the same method I used with anchored floating frames, except your frame would contain an image whereas my frame contained a text box.
You need to make sure that you anchor things to something sensible. Of course I want the surrounding box and label to move with the form elements if I moved their table to a different area on the page. That's why the frame containing "Account Access" is anchored to the PARAGRAPH in in the first cell of the TABLE and not to the PAGE. You gotta watch it, because you can move anchor points around by dragging them with the mouse, and if you're not careful, you might accidentally anchor something to, say, the character immediately BEFORE the table when you really meant to anchor it to the first character INSIDE the table. And anchoring something to a CHARACTER in a paragraph is different than anchoring it to the PARAGRAPH itself. So it can get confusing until you figure out what the heck is happening. Typically I zoom in the page and carefully click on something I want to anchor to rather than drag-n-drop an existing anchor to a new point. But this depends on how sophisticated my layout is. Sometimes you can get by with simple drag-n-drop if you have a simple layout.
