This is a simple HTML page with few icons.

Icon that behaves like an image:

Icon that behaves like an glyph (aligned to bottom of this text):

Changing icon color:

Big icon (showing various ways to do it):
Icons above should be aligned differently because they have different font-size. Vertical alignment is relative to font size.

Big icon (showing various ways to do it):
Icons above should be aligned identically because they are not using inline mode.

Rotation:

Flip: