Try searching Google for AS# slideshow tutorial and AS# gallery tutorial, where # is whatever version of actionscript you intend to use.
I am not that good with AS yet, is there a way to do this using no or a little actionscript?
You could do it using a little actionscript, but not none. If your large images are large files (byte-wise), the low-code version could result in a waiting game, but I'll give you an idea of how to approach it.
Create a movieclip symbol (Insert -> New Symbol and select Movieclip... name it "images" or something). The stage will show the new movieclip's stage and timeline.
If you don't want any image showing at the start, then starting at frame 2, insert a new keyframe (select it, right click-> Insert Keyframe) and drag the first image onto the stage. Use the align tool to make the upper left corner of the image be at the stage's center crosshairs. Move to frame 3 and repeat for the next image, and so on down the line.
Then, insert a new layer in the timeline, select the first frame, and in the actions panel enter: stop();
That will finish your image movieclip for now, so select Edit -> Document and you'll return to the main timeline. Then, drag your images movieclip onto the stage. label that layer "Images" (or something.
Create a new layer and name it Thumbs.
With the Thumbs layer selected, drag your first thumbnail onto the stage and convert it into a movieclip (Modify -> Convert to Symbol...). With that newly created movieclip selected, enter an instance name for it in the properties panel (thumb1 would be good). Repeat this for every thumbnail image you have, changing their instance names for each (thumb2, thumb3, etc). Position them as you intend them as you go.
The next step will be adding actionscript to the buttons, but I'll wait 'til you disclose which version of actionscript you plan to use.