Black background on PNG pics instead of white

good day Team xtemos,

We set a ajax woocommerce product display and we wanted to have a strict contol on picture dimension. we then set picture dimension on custom but our pictures are now using a uggly balck background for png pics.

Also using the custom dimension tend to deteriorate image quality.

While trying other image dismension settings we didn’t see any changes on the picture display.

Could you kindly have a look and point us to the right direction.
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