Previously, background-images were not properly optimized when inserted, whereas they should be just like regular images. This commit fixes that. It also changes the default quality (used for automatic optimization) to 75 as the difference is not usually very noticeable but can bring a big decrease in image size. task-2357332 closes odoo/odoo#59779 X-original-commit: 5d8c0aa0f7678f51e0a0931b0410a0273c7c7d1f Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>