When you upload an image its preview thumbnails are wrongly rotated, for example upside-down.
Embedded Data Mappings and auto-rotate
By default, Asset Bank will attempt to correct images that are wrongly rotated, for example if they were taken with a camera that was held on its side or upside-down.
It does this by looking in the 'embedded metadata' contained in the image. Many cameras now populate EXIF/XMP fields such as 'MakerNotes:AutoRotate' or 'XMP:Orientation' to indicate that the camera was rotated when the picture was taken. When an image is added, Asset Bank will look at this data and rotate the previews accordingly. Note: the original file is not affected by this process, i.e. if a user downloads the 'original file' they will indeed get the original file.
This functionality is happening because of an 'embedded data mapping' that is set up by default in Asset Bank, which maps 'Auto-rotate from camera' to the 'Orientation' attribute on 'upload'. Go to Admin->Attributes->Embedded Data Mappings to see the mappings that are set up for your Asset Bank.
Likely Cause of Wrongly Rotated Images
If Asset Bank is rotating images wrongly (for example, they don't need to be) then it is very likely that the image's rotation has already been corrected by some other software, which has changed the image itself but not the embedded data. Therefore, Asset Bank still thinks the image needs rotating. For example, in various versions of Windows if you right click on an image in Windows Explorer and change its rotation this will rotate the image but leave the EXIF/XMP data unchanged.
You can edit one asset and change the orientation of the file via the 'Rotate' option. Note, this will fix the preview and converted downloaded versions only. If the user downloads the original they will recieve the file as it was when uploaded.
For many images you can add all of these to your lightbox. Then select those that would need similar correction (e.g. chose all the images that need 90 degree clockwise rotation to fix), then go to 'More Actions > Bulk Update' and fix the orientation on them all at once. Repeat for other sets until complete.
Remove the embedded data mapping itself so that Asset Bank does not attempt to correct the rotation of images on upload. To do this, go to Admin->Attributes->Embedded Data mappings, and click the [X] next to the mapping 'Orientation [Other] Auto-rotate from camera'. Note, this may solve the issue for a few, but create an issue for the majority where the correction was right.
If you want to keep the above mapping, for example if you find it useful in correcting the rotation of images that have not been pre-processed by other software, then another option is to ask the people who are correcting the images before they are uploaded into Asset Bank to do so using software that also changes the embedded data value for the rotation. I.e. fixing this aspect before upload to Asset Bank.