Image file size changed after saving

[baibai92]

System information:

• Windows OS version: windows 10 2004
• ImageGlass version: 7.6.4.30

When I use the function: save image as, the saved image size has been changed. I don’t know if the others have changed.
I want the saved image to retain the same attributes as the original image, just like copying.

On the left is saved, and the right is the original
@d2phap

[d2phap]

IG is set to save the image as 100% quality by setting "quality" in Magick.NET library. In other apps (MS Paint,...) it's about 75-80%
I will add an option to change this value in the next release.
Also reported at #829

[fire-eggs]

The image in question is a PNG image. Image quality "normally" doesn't apply to PNG.

When IG saves at 100% quality, the image size usually increases. The OP's image size has decreased.

We'd need to have a copy of an image which shows the problem. Did IG strip Exif or other Metadata? Change the bits-per-pixel?

[fire-eggs]

Before I forget (again!) - the image you show is very nice! Would you share the source? Thanks!

[baibai92]

I tried different formats and different sizes of pictures, some became bigger and some became smaller. Now I provide these files, you can try。
Link：https://cowtransfer.com/s/2f99346b322449

[baibai92]

@fire-eggs

[fire-eggs]

Thanks for the samples!

What IG needs to do is save the image using the same configuration the image was loaded with.

As Phap points out, in the case of JPEG, IG is potentially using a different quality setting. But there is more to it:

• BMP files: Magick.NET is writing out additional metadata (Red Mask, Green Mask, etc) which increases the file size.
• JPEG: in addition to the quality setting change, Magick.NET is writing different metadata.
• PNG: Magick.NET is writing additional metadata, but is using a more effective encoding, making the written PNG overall smaller!

[d2phap]

Add option to change image quality in Settings > Edit tab in IG Moon: https://imageglass.org/moon

[mirh]

I cannot find that option in 8.0.12.8.

[d2phap]

@mirh
You go to Settings > Edit tab.
Or you can send me a screenshot

[mirh]

Yes, I have seen your scre
Nvm I had a brainfart.

[manyfew]

I just rotated a JPEG 90° right once. The file was originally 12.2 MB, and after saving it became 18.7 MB. If I rotate it using the Windows Photos app the file size doesn't change. I wonder if this could be optimized.