Shrinked images look blurry

Steps to reproduce :

• On a clean XWiki instance, go on Sandbox.WebHome
• Edit Sandbox page in WYSIWYG mode,
• Import image that has some text in it.
• Shrink the image it down a little from the bottom right corner of the image or from the image sizing options.
• Save & View

Result: a blurry image - the effect on the image text especially

Before the shrink:
on 12.10.2

on 13.4.5

After the shrink:
on 12.10.2

on 13.4.5