MorphOS comes nowadays with text editor called Scribble. It has syntax highlighting and couple other features for HTML too.

I'd recommend ShowGirls (included in MorphOS) and ArtEffect for effects editing and converting, but then also PPaint for pixeling of small details. PPaint is fine for creating GIF anims too.

FXPaint2 has nice HTML gallery creation option, it comes with many predefined themes and you can create own themes too. It has some bugs, but you'll learn to avoid the crashes :)