I’ve whipped up a (VERY) basic gallery for you to play with.
It’s much easier and quicker to do stuff with action script than it is to do with manual effects.
Look at the attached gallery.swi
If you can’t open it because you have an older version of swishmax, use the code below

Add all your large images to the scene and give each one a unique name in the SHAPE tab and tick the target box.
This just allows you to control this image later with action script
I added five images, each named image#, where # is a unique number.

On Scene_1′s SCRIPT tab enter the following

onLoad () {
// Sets the five named and targeted images to invisible
image1._visible = false;
image2._visible = false;
image3._visible = false;
image4._visible = false;
image5._visible = false;
}

function resetImages() {
// Resets the five named images to invisible before making one visible onRelease
image1._visible = false;
image2._visible = false;
image3._visible = false;
image4._visible = false;
image5._visible = false;
}

Create and place the corresponding thumbnails and for each one add this to it’s script

on (release) {
// Call the function to reset all images to invisible
resetImages();
// Make selected image visible
// Correspond this next line to the image you want to show for this thumbnail
image1._visible = true;
}

Good luck

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