FM12 - "Black" images in HTML5 output

Hello

I'm using Framemaker 12, and I work with HTML5 output to publish online helps.

In my FM files, I use PNG images which are in anchored frames.

My problem is, after I did the HTML5 output, my images appear "black" as you can see below. Any idea about where this problem comes from would be greatly appreciated !

Thanks a lot.

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