Hi,
If you want, we have a french support section (which is managed by our support team too).
www.hikashop.com/forum/5-support-en-fran...french-support-.html
In Hikashop, we change how the thumbnails are displayed in the product page. It uses some more recent functions in the helper image (also used by the gallery system).
Do you have a view override for your product page ? (on "frontend | your_frontend_template | product | show_block_image" more precisely)
It is possible that HikaShop does not have the right to create new files in the folder "upload/thumbnail_400x300/".
Please check the write permissions for the upload folder and the sub folders.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.