Deleting the build cache using WebSupport build

[geeksambhu]

Is there any way to delete the build cache while using WebSupport.build as in make clean in sphinx ? I need to delete the build cache because if the image with the same name but different image file content is built one or more time using WebSupport.build the same old image will be shown unless and until the name of the image is changed.

[shimizukawa]

Can you provide a small project that reproducing the issue?