tif files upside down

[JELSTUDIO]

Using Avisynth 2.61, build may 17 2016, 155742, VC6

TIF files that are 32bit (8x4, so I'm assuming it is TIFs with alpha-channel) show correctly, but all TIFs that are 24bit (8x3) are upside down.

What would an easy fix* for this be (besides reconverting to an image-format that does not support alpha-channel), to get all TIFs to show consistently one way or the other?

Can some kind of batch tag-edit fool avisynth into seeing all images the same way?

Or some avisynth code I can add in the script? (I have tried the tag: "pixel_type", but no difference in behavior seen from that)

The thumb-nails in Windows all show correctly.

Tips/tricks welcome :)
Thanks
JEL

*the inconsistency comes from a batch converter I'm am using to generate the TIF-sequence from a BMP-sequence, and for some odd reason it doesn't use just one type of TIF when it converts. I don't know why it behaves like that but perhaps it's a bug in that converter program. Nothing I can fix myself for now, so looking for ways to bypass this oddity when doing the avisynth steps on those TIFs.

[Selur]

Or some avisynth code I can add in the script?
FlipVertical()

[wonkey_monkey]

I assume the sequence loads but then individual frames are flipped, depending on whether or not the source image for that frame was RGB or RGBA - if so, a blanket flipvertical won't help.

Which filter are you using to load the image sequence? You could try alternatives to that.