In all major browsers: as the question states, a parent <div> container (whose height is not set) over-sizes its height to fit a child <img> element (for instance, a 300-pixel tall image that is the only thing inside the div). The over-sizing is usually about 3 to 5 pixels, and appears at first as img margin-bottom or div padding-bottom might look.
However, using absolute positioning, it is clearly demonstrated that the bottom of the div is below the bottom of the imgby a few pixels. It might not ruin a website’s design, but it is a hurdle to overcome in certain situations. I have made a fairly detailed fiddle demonstrating this issue here.
- Why is this standard practice in web browsers?
- Is this meant to compensate for something? It seems unnecessary.
- Is this a bug, or a soon-to-be antiquated feature?
EDIT: Thanks to the answerers/commentators below, I know the reason is that an
<img>is treated by default as CSS
display:inlinewhich preserves whitespace around the element.
Changing it todisplay:blockcompletely fixes the problem by
eliminating whitespace around the element.
Notes: This over-sizing can be averted by giving the image child element a CSS property of float:left or float:right, etc., but this is a workaround, and as such is not the answer to the question. One reason this can be problematic is if you already have other float elements layered in front of the div child image (float overlap not allowed Firefox, Opera, IE. float overlapping only seems allowed in Chrome and Safari using CSS position settings). Thanks!
Add display:block to your image. I think that will fix the problem.