[Plugin: NextGEN Gallery] Degraded picture quality

It seems the picture quality is degraded when displaying pictures from galleries. Eg. one picture is 298 kb before uploading, it is 298 when previewed in the gallery, but it is 295 when viewed on the site (based on image info). It also appear less vivid, and not so sharp. Is this as it it supposed to be? What is happening between the gallery and the display of the images? Under Gallery – Options – Images – Image settings, the Image quality is set to 100%.

Can something be done to preserve the best possible quality?

NextGEN Gallery ver. 1.3.3