in Finder there is a column header with the name dimensions. It gives the correct width and height.
For those portrait oriented pictures I have to open them in e.g. preview, rotate them 4 time or back and forth and save them to change the exif width and height data. This is a lot of work of course so I want to know what date jAlbum or its skins are using to determinate the correct orientation of portrait pictures.
Apparently the exif tag "orientation" should be used. All portrait photos have an Orientation tag with the value 90 CW (clockwise)
Please give us access to one untouched original that shows this problem. It's probably going to be too large to attach to a forum message, so please upload it somewhere and give us a link. Or just create a Minimal album with that one image, choose Link to originals, and upload the album.
jAlbum doesn't seem to have any trouble with that image. It displays in the proper orientation in the Explore view, and when I make an album, both the thumbnail and slide image are correct.
The EXIF information on width and height is reversed, but the orientation flag is correct. So, the net effect is that the image is shown correctly. And jAlbum doesn't change any EXIF information - it takes what it's given.
It also shows correctly in every image viewer I've got on my PC: Photos, IrfanView, Picasa, paint.net, etc.
Don't know what you've done, but I simply don't have any problems with that image:
(demo album removed)
ETA: A-ha!! The problem is that you're using Link to originals. That means that jAlbum isn't touching your original image - it's just planting it in the album. So, it never has a chance to correct the orientation. That image is just fed, raw, to the browser, and the browser can't handle it.
If I re-save the image in IrfanView, for example, and tell it to correct the orientation flag, it works properly. ETA: It also gets fixed if I simply re-save the image in paint.net or Picasa - in short, almost any image-processing application can fix the orientation!
The other solution is to choose Link to scaled-down images only, but give it very large image bounds so that it doesn't resize the image.