How can I eliminate spacing between inline elements in CSS? [duplicate]

This question already has an answer here:

I have a div with a bunch of image tags inside, here is an example:

Foo1 Foo2 Foo3

Because there is whitespace between the tags, browsers will display some whitespace between the images (Chrome decides on 4px). How can I tell the browser to show NO whitespace whatsoever between the images, without placing the > and < directly next to each other? I know letter-spacing applies in addition to what the browser decides to use, so that's useless even with a negative value. Basically I'm going for something like Twitter has at the bottom of their home page. I looked at their code and they're using an unordered list. I could just do that but I'd like the technical explanation for why there appears to be no way to eliminate the white space from between these images.