[Bug] ATI1N and ATI2N issues

[SirYodaJedi]

(or at least just for ATI1N)

I just upgraded to this version from Neil's version for the v7.6 and BC6H/BC7 support. I noticed that while the plugin does correctly report ATI1N in the metadata (actually, doesn't always), it does not generate thumbnails for images using the format. While ATI2N is basically deprecated by BC7, ATI1N is still the best texture compression format for opaque greyscale textures, so I do use it and would appreciate being able to preview them.

EDIT: Actually, seems like ATI1N sometimes bugs out and gets reported as ATI2N:

[SirYodaJedi]

It seems that there are more bugs with these formats than I thought. I have updated the issue topic. Attached are the original v7.4 textures, as well as the converted v7.6 versions (vtex2.exe convert -c 9 -f ati1n input.vtf)

v74.zip
v76.zip