The marquee element has various implementations, in part because there was no published specification for it. In HTML5, an element is precisely defined, and HTML5 drafts require marquee support , as defined there . (Drafts also declare it "obsolete" and "inappropriate", but this is what they say to the authors, the requirements for implementations are different). However, there are still limitations and differences in support; see, for example, MDN on marquee .
In this case, it does not look like an image, but the behavior="alternate" attribute causes a problem. If you delete it, the image will also move across Chrome.
This is an implementation error, not a lack of support. Checking the DOM in Chrome shows that the behavior property is alternate as specified, but it just doesn't work. If you add a border to the marquee element in CSS, the image starts moving one at a time, but only a few pixels left and right.
If you really alternate direction, it is best to use a different technique instead of marquee . For example, a simple moving image can be implemented using JavaScript, so that the position changes in a loop using a timer, and then you can also easily implement a variable direction. Alternatively, it may be simpler, but not so reliable (due to limited browser support), you can use CSS3 animations.