Changing colors should be part of the default system, in a similar fashion to RMXP. I just double checked the manual, and you do it like this in the show text event:
/C[n]Colored Text
Where the n represents the color's number in your system graphics settings. As for icons and pictures, those are a bit more complex. Those will require scripts, and depending upon exactly what you need, it may require you to post a script request for it.