I have added my product's image and its additional images.
My prefix for Medium and Large images are _MED and _LRG respectively.
My image sizes are as follow:
*Large Image _LRG*
375x500 pixel
Directory: /images/large/for_kid/hair_clips/

*Medium Image _MED*
188x250 pixel
Directry: /images/medium/for_kid/hair_clips/

*Additional Images thumbnail*
75x100 pixel
Directry: /images/for_kid/hair_clips/

*Product Image thumbnail*
375x500 pixel
Directry: /images/for_kid/hair_clips/


This is what I have named and placed for my image files:
*For thumbnail images*
/images/for_kid/hair_clips/GlitterStarHairClips.jpg
/images/for_kid/hair_clips/GlitterStarHairClips_6767-p.jpg
/images/for_kid/hair_clips/GlitterStarHairClips_6768-p.jpg
/images/for_kid/hair_clips/GlitterStarHairClips_6769-p.jpg

*For _MED image*
/images/medium/for_kid/hair_clips/GlitterStarHairClips_MED.jpg

*For _LRG images*
/images/large/for_kid/hair_clips/GlitterStarHairClips_LRG.jpg
/images/large/for_kid/hair_clips/GlitterStarHairClips_6767-p_LRG.jpg
/images/large/for_kid/hair_clips/GlitterStarHairClips_6768-p_LRG.jpg
/images/large/for_kid/hair_clips/GlitterStarHairClips_6769-p_LRG.jpg

Please visit my website here for example.

Problems:
My additonal images are not displaying the Large images when I click onto the Thumbnail.
All images displaying are taken only from the directry: /images/large/for_kid/hair_clips/
I thought the problem might be due to the many folders I have created for my image folders. I reduced to one or no folder for my image but without avail.
What went wrong?

Regards
Cheng King Xiang