Managed .png attachments get converted to .jpg with quality LOSS



I have an issue. I just posted some quality scans in the Blank Blu-ray Media Tests sub-forum.

I always grab all my disc scan images as png.

I upload them with New Post / Go Advanced / Manage Attachments.

However, regardless of whether my files are (with correct suffix) in .GIF or .PNG or .JPG format, they always get converted into .JPG format once I upload them in the “Manage Attachment” window.

This results not only of increase in file size, but also severe loss of quality.

Case in point:

Original PNG (at an external site)

Exact same PNG file uploaded via Manage Attachment feature into a new post which auto-converts it into .JPG:

How can I avoid the auto-convert to jpeg feature of attachments?

I know I can upload to an external site and just embed those images, and bypass the problem, but those external sites are not reliable and they keep destroying the images…


You’re hitting the maximum dimension limit.

When you attach files, you get a file size limit & a dimension limit (where applicable). For me, I recall it being a max width of 865 pixels (no height limit) and somewhere between 300 & 400 KB file size. That may have changed since I last looked, or your limit may differ.

In this case, since your image seems to be wider than the max allowed, it gets resized (a lossy process) and saved as JPG (also lossy & compararively inefficient, as you can tell).


[QUOTE=Albert;2787592]You’re hitting the maximum dimension limit.[/QUOTE]

I must say that’s really stupid coding to enlarge file sizes by re-compressing them from 23kB png to 89 kB jpg, because the pixel dimensions are too high :smiley:

Guess I need to start scaling the image crops to smaller dimensions.

Thanks for letting me know!


Correction: the size is 585 KB for images. I’ll let you double check if it’s the same on your end.


the auto-conversion is triggered solely by pixel dimensions of the file, and not file size. That’s just stupid, imho, considering the file size limit is not exceeded, don’t you think?

My original PNG is smaller in file size (15 kB) than the auto-converted JPG file (77 kB), not to mention it is 1/39th of the file size limits set for .png attachments).

If the image pixel size is too large, the forum soft could scale it via HTML/CSS or then rescale the image (without destroying the quality by converting it to low-quality jpeg).


No, I fully understand. I just needed to clarify for future scenarios.

It would be nice if the software could scale images which are already of a decent file size. Alas…

Maybe something can be done about it.