Can someone delete the double postings?
What is the actual length of your sequence?
The 12 frames are they adjacent to each other or you want to export just every lets say 21st Frame? If its the latter, you need to increase the speed in the sequence. Maybe you need to nest the sequence first.
Is setting the in/out points not working for you?
So, suppose I'm working at 25fps and I want to export 50 frames, I set the in/out points so that there are 2 seconds of material between them.
I have many sequences to do so there is no actual set length as such but I will use an example..
The sequence I want to extract from is 4.5 seconds long, and I need 12 frames extracted from this.
I am kind of new to premier so please forgive me for not fully understanding everything that it does, I have set the in and out at the start and end of the sequence I require extracted, if I set it to 5 fps then I get 22 PNG's from this extraction, which is as close as I cna get to 12 at the moment. The sequences are all different though so bear that in mind but I always need 12 images.
What do you mean by nest ?
And the speed option sounds like it may work, I will have to test it out first though, is this an easy option to change and how would one do it?
Nesting: if you take the sequence in the project panel and dragg it onto the "create new object" icon (looks like a sheet with folded edge), the sequence will be packed into a new sequence. This is called "nesting". Another way to do this is selecting all clips on your timeline and rightclick>nest them into a new sequence.
Speed Options: If you slect this nested sequence (like selecting a clip) rightlick>speed/duration and set duration to 12.
Sometimes nested sequences do behave strange when speed/duration is changed though. Let us know if it worked.