I'm not sure if this is a generic problem, but see: https://secure.wikimedia.org/wikipedia/en/wiki/Enriched_uranium
The following image's text doesn't scale with the image: https://secure.wikimedia.org/wikipedia/en/wiki/Image:Uranium_enrichment_prop...
The image link in the article is: [[Image:Uranium enrichment proportions.svg|right|200px|thumb|Proportions of uranium-238 (blue) and uranium-235 (red) found naturally versus grades that are enriched by separating the two isotopes atom-by-atom using various methods that all require a massive investment in time and money.]]
I've checked on Firefox 3.0.3 and IE 7.0
I believe that this must be a recent change - I check that article semi-regularly (it's on my watchlist along with other nuclear topics) and I don't recall seeing any problems with it...
