DescentBB

Is that possible? For example, I would like to import the D1 lava to a level in D2, and its animation has four frames. How to go about it? Is it even possible using just DLE-XP? If not, could someone suggest some alternative utilities?

Two ways.
1) Combine the four frames into a single 64x256 texture (where the larger dimension is the vertical one). Import that into DLE-XP. Won't work for regular D2 though.
2) Find another lava texture with four frames, click "show all frames", and replace them frame by frame. I forget whether this works very well though. You might be able to do it with DTX2 if not (if you can run DTX2 anyway).
3) If there is no lava texture with four frames, find another ordinary texture with four frames, repeat step 2 above, and use it as a secondary texture overlying a lava primary texture.

...er, that's three. Never mind!

The "show frames" option doesn't do anything for me, no matter if it's checked or not ;<

Show frames should display an entry in DLE-XP's texture list (drop down box below the texture image in the texture tool dialog) for every single frame of an animated texture in DLE-XP.

If you are planning to build a D2X-XL level, using a single (uncompressed!) TGA texture containing all frames stacked vertically would be the better approach though.

Nah, I want it to work in Rebirth.

Hmm. Show frames only seems to work for doors. Well, I guess you could try DTX2...

Necrobump.

I did it in DTX2. took some work, though, and quite a bit of thinking. The biggest problem were the D1 monitors, in the transition some of them lost some frames. The pog's ready, though.