InDesign - Images with white background that are not white when exported

[Uxuemgm]

Hi everybody!
I'm doing a layout and it has some illustrations made by me, I've moved them to Photoshop and in theory the background is completely white.
When I view it in presentation (Shift+W) it doesn't have any problem, as you can see in the first image. But when I export it, it creates a difference with the background, as you can see in the second image. As if it had an off-white background, and it makes a difference.
I've tried with the multiply effect, but it doesn't affect it in this aspect.
Thank you very much!

[BobLevine]

Export it to what? Export it how? How are you viewing it?

[Uxuemgm]

Maybe it's the program I use to view it....
I click on File/Export.../Adobe PDF and the options are these:

When you asked me how I'm viewing it I opened the PDF with Firefox and it didn't show the off white box, neither opening with Adobe Acrobat Reader DC, but when I open it with PDF Architect 7 it does. That wouldn't be a problem for the majority of the people, right? ( Not many people use that program...) Would it be a problem when printing?

Thank you so much!

[rob day]

There isn’t a problem with the images—the backgrounds are all 255|255|255 RGB white. The images don’t have a color profile assigned, so your export to [High Quality Print] exports the placed images with no profile. You might try exporting using the PDF/X-4 preset, which will assign your InDesign document’s RGB profile to the images on export, and see if PDF Architect wants a profile.

[rob day]

Can you share the Photoshop illustration via Dropbox or your CC account?

[Uxuemgm]

The link is from wetransfer and contains: the original Photoshop and the jpg. It doesn't matter if I use the original or the transformation to jpg, I still see the off white box.
Maybe if I save it with a transparent background it will work?

https://we.tl/t-lnJIfg5FaW