Setting CSS properties to max-width and max-height to avoid distorted and blurry upscaled icons

I noticed that in the NuGet Gallery all package icons get scaled to 50&nbsp;×&nbsp;50&nbsp;px / 128&nbsp;×&nbsp;128&nbsp;px. That looks very ugly when the package icon is not square ([example](https://www.nuget.org/packages/Modernizr/)) or has a low resolution. That will result in blurry upscaled icons.

I think max-width and max-height is much better here. In addition I suggest changing the maximum icon size to 48&nbsp;×&nbsp;48&nbsp;px, because that is a common size for icons.