A reader wants to open an image sequence and work with it as video, but the option is grayed out in the Open dialog box.
The clue to solving this puzzle is to see the Format choice that Photoshop CS4 has given, Photoshop Raw. In this case, the reader has exported a Tiff image sequence from Avid and wants to work with it in Photoshop. Fair enough ... no problem, right?
The problem has to do with the way the user configured Photoshop's Tiff image handling - he set it to prefer Adobe Camera Raw for Tiffs. With this, the Open dialog is looking to send the Tiffs to ACR, not directly into Photoshop. A simple change of settings in the Preferences fixes the problem.
Browsing again to the folder containing the image sequence and clicking on the first image in the sequence produced this result in the Open dialog.
The Format is now set to Tiff and the Image Sequence check box is available. All that's left to do is to check the box and click Open.
Then, set the Frame Rate and click OK.
And there you have it, you can now work with your image sequences as video in Photoshop CS4.