Delay of Image contained in a gif animation is a frame duration.
You can set Frame Duration for each frame on you choice from the list.
When you add new picture (add frame) to the list, new frame will inherit frame duration from previous
one. You can set duration different than inherited any time.
Values shown in milliseconds.
For existing animated GIF images - to modify animation you need to split animation first. Then change frame duration for each image from the list.
In our example two different frames have two different values: 2000 (means 2 sec) for
First Frame and 100 milliseconds for Second Frame.
See how would look this image if frame duration is same for both frames and equals 150