Spry Table: size of detail regions

I have a table with 5 items. each item is linked to a different image (the
detail region).
I want to have different sizes of detail regions : so when I click on item 1
of the table, the detail region (image) that opens has a X size, and when I
click on item 2 of the table, the detail region (another image) that opens has
a Y size. etc...
I am using an image placeholder to place the image of the detail region: it
may be the source of the problem. But if I don't use an image placeholder, the
image/detail region does not show.

Many thanks in advance