Attached images resized to thumbnail appears to be blurry

Images attached to Confluence resized to thumbnail appears to be blurry or lose quality.

Step To Reproduce

1. Create a simple page.
2. Upload all the attachments: attach2.jpg attach3.jpg
3. Insert all of the attachments/images and resize the thumbnail. (resize the image smaller or change the px size)
4. Save and observe the results.

Expected Result

Thumbnails should preserve the image quality.

Observed Result

Thumbnail image quality is tampered.

1. Confluence 5.5.6
2. Confluence 5.6.3

Workaround

Resize the image where it still preserves the quality.

Note: Confluence 4.3 does not have this issue, it renders the thumbnails perfectly. You can resize to any px size (smaller) without losing the image quality.