Hikamarket vendor page do not show the vendor image

-- url of the page with the problem -- : www.realflightshop.com
-- HikaShop version -- : 2.6.4
-- HikaMarket version -- : 1.7.2

Hi

I found that in my site of vendor page, the vendor image can not shown and appear the message of warning shown as follow

"Message

Warning ! The image aerosoft_logo_1877282814.png is too big to be processed because of the memory limitation on your server. Either use a smaller image or increase the memory_limit parameter of the php.ini of your server."

I have check the server memory and it is OK, also the image only 3~6 Kb and 250*175 pixle , it's not big.
I have try to upload another bigger picture with 640*1000pixle , and it can be show, but change back to 250*175 pixle image, it's show the warning again.

Do you know how to solve this.

Thanks!