AdeV,
Indeed!
But there some pics (above) that the thumbnail now is horizontal because I edited the image and rotated it -90º, and so when you click it the resize will show it as I intended to be seen.
I mean I cheated the resize tool in order the pic be shown "right".
See below pic showed with the hint on original, and after in the one edited.
Cheers
VP
Hey VP - apologies, I didn't reply to you (been v. busy...)
I think, in order for the thumbnail/main image to display in the same orientation regardless of how you rotate it, you need to make sure you save it without any EXIF data. The EXIF data (which most image editors preserve) tells the display device what orientation the camera was in when you took the photo. So where you've rotated the image, the display device (computer) sees that the EXIF data says "rotate 90", and it rotates it... and now it's "wrong". Equally, I'm not sure that the software that generates the thumbnails for the site honours the EXIF data (I'd actually be surprised if it did), which would explain why the thumbnail is portrait but the image is landscape, or vice versa...
All I can suggest is, when you modify a photo for the site; find & de-select the option to save EXIF data. e.g. for gIMP (the defacto standard Linux image editor), when you export a file, the options dialog that pops up has "Save EXIF data" checked by default - un-check it and the photo will appear how YOU want it, and not how the computer thinks it should be.