Some implementations of mobile ADE have scaled images with font size, but I don't think most versions do. I reported scaling images (so that they got larger than the screen) as a bug in the original Hanlin ADE, and it was taken out of later versions.
The easiest version for everyone to check against is the
Sony eBook Library, since its viewer is a desktop implementation of mobile ADE. I'm pretty sure it does not scale images with font size. The Desktop ADE is not currently using the same code base as mobile ADE, but that will reportedly change some time this year (the next major update to desktop ADE will be more like mobile ADE).