How to Watermark multiple images with different dimensions in Photoshop ?

The "Picture Processor" script will do this and can be found in the "PSCS Scripts" section http://www.ps-bridge-scripts.talktalk.net/

Good luck.

1. Open an image to watermark. We must have this open before we start recording an action or else it will keep opening this image and watermarking it over and over again.
2. In Photoshop go to Windows >> Actions
3. At the bottom of the Actions Palette you will see a little folder icon, click on it and create a new folder to hold you action in.
4. Once you have a folder to hold your action we need to hit the Create New Action button (next to the new folder Icon we just used.)
5. Give our new action a name and set a function key (if required.)
6. If the record button is not already depressed which it should be by default, hit it now to start recording our action. (located near the folder icon again but this time to the left)
7. Now that our action is recording go to File >> Place
8. When the dialog box comes up navigate to your previously created watermark file.
9. Hit the Place button
10. Position the watermark as you would normally have it (default is dead center) and hit enter.
11. Go to File >> Save as,navigate to where you want your watermarked images to finish up and hit save. DO NOT CHANGE THE FILE NAME if you do when you play the batch it will name all the files it saves the same over-writing each other.
12. Close the image we just watermarked.
13. when a save dialog comes up do not save the image.
14. On the Actions Palette hit stop recording.
15. Our Action is now recorded.
16. To process an entire folder of images we go to File >> Automate >> Batch
17. Select the folder in which your images are currently
18. Select the folder you wish to save the watermarked copies too.
19. Hit OK
20. Photoshop is now watermarking all the Images in the selected folder for you.

This is not going to work as the logo needs to be resized to fit each document. Each document could be vastly different in size, therefore actions can not work, a script is required to work out the placement and size of the logo so no matter what size the document the logo will appear as the same proportions and in the correct position.

The "Picture Processor" script does this.

This video, like must help you.

How to Watermark Multiple Pictures in Photoshop CS6 - YouTube

Wrong! that ONLY covers documents of the SAME size (landscape or portrait).

Now try that withe a document that is :

600x600

1200x600

2400x800

3000x2000

Your methed will NOT work. The script WILL work.