So I've managed, after much frowning and an attempt at installing MultiDOS that left me swapping disks literally about 80 times, to find a way, albeit convoluted, to transfer files from my Amiga to my PC (running Linux, though I have access to Windows).
However, when I tried to convert my DPaint pictures from ILBM, using a Linux ILBM to PPM converter, it garbled all of my halfbrite image palettes, outputting
matt@hayashi:~/amiga/192.168.0.1/~matt/lowres$ ilbmtoppm -isehb random\ g > rg.ppm
ilbmtoppm: warning - non-square pixels; to fix do a 'pnmscale -yscale 1.1'
ilbmtoppm: unknown chunk type DPPS - skipping
ilbmtoppm: warning - probably shifted 4-bit colormap
ilbmtoppm: use "-adjustcolors" to scale colormap to 8 bits
ilbmtoppm: input is a 6-plane EHB ILBM
Basically, it got the main colours right, but the half-brightness colours randomly remapped to other colours, and I'm not sure why.
Anyone know how I could rectify this, or a better converter/way of loading ILBMs?