Step 1: Create an imceimage field to use later

If you already have a CCK imceimage field setup for a node type, which can handle multiple images, you can skip this, but you still need to know the machine readable name of your field.

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Step 2: Setup IMCE profile for the thumbnail prefix

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Step 3: Setup jCarousel Block in the admin/settings

image field name...
image field type...
imceimage thumbnail prefix...

Step 4: Upload images

edit node and add the imceimages...
create thumbnail (as per profile set)...
save

That's it!

Step 5: lightbox (optional)

You can enable lightbox if you have it.