XnView Software

I tried using XnView MP, PIL, and OpenCV to stitch together the tile map I needed. I found that for levels 7 and 8 (32768*65536, 65536*131072) output PNGs, there is a strange phenomenon in the preview in XnView:

At 100% zoom, the bottom 1/3 of the content cannot be displayed normally, and the ...

1.7z As you know, the number of map tiles is usually very large, making it difficult to handle manually, which is why the 'Join images' function is needed. The tiles I need to stitch are numbered starting from the bottom left corner, increasing upwards and to the right. This requires you to provide ...

I need this action too, and I want to using it on 23,875 files in 1,729 folders, and "Change color depth- 24bits" can't do that, I put a file here maybe you can try it.
Orignal File:
Chap01_Prop_Under_LargeSign_02_PackAlbedoMetal.png
Remove alpha channel
Chap01_Prop_Under_LargeSign_02 ...