Step 1: Go to File menu, click Scripts, then choose Load file into stacks.
File > Scripts > Load file into stacks.
Step 2: Click Browser...
Step 3: After that select all picture you want to make GIF. After that click OK button.
Now we waiting for Photoshop loading all photo.
Step 4: Click on Create Frame Animation.
Step 5: Click on Make Frames From Layers.
Step 6: Select all layer by hold Shift button, then select start layer and end layer. Choose time you want set for each slide picture, in this tutorial I choose 0.1 seconds.
Step 7: Choose Forever if you want loop this GIF picture.
Step 8: Go to File menu, click Export then click on Save for Web...
You can see this video for more detail:
























