[WB] New: Add css styles for images

[leboem]

Info:

• img-left: left aligned float image with width 300px

• img-right: right aligned float image with width 300px

• img-center: same as align-center

• [x] Ran local test?

[kyaso]

Looks good!

I just changed the width of the two centered images in the DD post (401f426). (note that I didn't change the width globally)

[kyaso]

Also, we maybe should squash the commits at the end before merging.