Hello,
I just opened .pptx document that I had been working on this past 3 days, and I find all but 2 or 3 of my images 90% transparent.
How can I revert to no transparency ?
Can you upload a sample presentation document of 2 or 3 slides from the offending file?
My first thought is that you might have inadvertently changed the transparency on something like Default Drawing Style in the sidebar, Styles pane.