Scanning - filesize changed with same scan settings (?)

[PieterJO]

EDIT: This more or less solved but can't remove the post.  I overlooked a setting in the newly d/l scan software that sets the quality by default at 75%. By shifting this to 100%, the file size is still 25% smaller than it used to be, but I guess i shouldn't worry about that too much anymore. Thank you.  

Hi, I recently purchased a new laptop (Pavilion 15 with Windows 11) and installed the recommended software for our ENVY 7921e All-In_one: HP ENVY Inspire 7900 series (NET).  My previous scanning software for the same all-in -one device was HP ENVY Inpsire 7900 series PCL3 (V3), running on a Windows 7. 

We are currently scanning our collection of  paper family photos.  As far as I am aware I am using exaxtly the same settings in the new software on the new laptop as on the old system. Still the file size, after software saving it to the C drive, on the new system is only a about quarter of what it used to be. While the dimensions are the same.

Example file size differences:

I did the same scan (not moving the photo on the scanner glass at all) on both laptops with the recommended software:

600DPI : old system/software 1,33 MB, new system/software 359kb

1200DPI Old system : old system/software 4,6 MB, new system / software 1,2MB

On the laptop screen I can' t really see the difference in the final result, despite the difference in file sizes. However, i am concerned that the new software/system is doing something automatically to reduce the filesize which I assume must have a negative impact on the final result, although it's not all that visible on a small screen.   

Anyone any ideas why these filesizes are so much different? Might it be a setting in Windows 11 somewhere?

It is also remarkable that - when selecting the 1200DPI in the scanning  tool - you get a warning that the file size will be very large. Well, 1,2 MB is really small for a high-res scan isn't it?