Cannot bring to front images in pdf form

[suvisufi]

I have a pdf form I need to fill but I'm having problems with images. I can add text in the "text box" but when I add an image it goes behind the "image box" in the form, i.e. is not visible

"Bring to front" and "Bring forward" won't do anything.

Apparently the form itself does not have any issues since my colleague can add the images.

I use Acrobat Pro online with Macbook.

[Thom Parker]

I believe you are talking about two different things, page content and annotation objects. Page content is all the text, graphics, and images that are part of the PDF Page. Annotations are rectangular object that float over the page content. Annotations inclue all of the text markups like highlights and crossouts, they include the drawing objects like squares and circles. And most importantly, they include form fields. 

When you are in "Edit PDF" mode, you're editing the page content. The text boxes and images in this mode have zero relation ship to the annotations. You can add "text" in this mode. It is often described as a "text box" but its just plain page content.  These text boxes and other page content items provide options for moving them up and down the page drawing stack, the "Bring to front", etc. options. These options only affect page content items. Annotations are always drawn over page content, never under.  

See this video that covers the internal structure of a PDF. At 5:36 there is a nice graphic that explains this concept:

https://www.pdfscripting.com/public/FreeStuff/AcroForm_Concepts/Part1g_WhatsPDF_mp4.cfm