@persia
Why can't you? I can take camera and download photos with Amiga easily (done that with about ten cameras and all have worked either with PTP or USB mass storage), I can edit them as I need and I can create web pages either automatically or by hand from batch converted images etc. As you said, basic stuff, which can also be made with Amiga.
TVPaint... uhm.. why should paint program support mp3? And for scanning there's different programs.
For massive pictures, you probably need to take some program which has internal virtual memory system, like ArtEffect.
But anyway, slipping again from the original still not answered question, is there modern equivalent for DPaint, which does easy pixelling? For example for (animated) gifs and other web graphics, icon desingning, game gfx, etc possibly low color and small size pixel editing.
For other uses like photo editing etc there are much better alternatives than DPaint on Amiga too.