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Not planned Thumbnail Attachments

Amaury

Well-known member
#1
When you attach an image as a thumbnail, the quality is reduced a bit -- most noticeable thing appears to be the sharpness -- and it would be nice if quality didn't degrade.

Thumbnail Example:
Saint Patrick's Day.png

Full Image Example:
Saint Patrick's Day.png

You can tell the thumbnail isn't as clear by how the time on my computer looks.
 

Brogan

XenForo moderator
Staff member
#2
I'm not sure I understand the suggestion.

A thumbnail by very definition is not going to be as clear as the larger image; it's a fraction of the size.

Other than that, both images in your post link to exactly the same file/image.
 

Amaury

Well-known member
#3
I'm not sure I understand the suggestion.

A thumbnail by very definition is not going to be as clear as the larger image; it's a fraction of the size.
That's my suggestion exactly. :p Keep the same sharpness it would have as a full image.

Other than that, both images in your post link to exactly the same file/image.
Correct, but notice how it's not as sharp in the thumbnail. It's easy to tell if you look at my computer time. :)
 

Amaury

Well-known member
#5
How exactly can an image which is a fraction of the size of the original have the same resolution?
That was my thought as well. However, it should be possible, shouldn't it?

For example, the unedited version of my current avatar has dimensions of 1300 x 867 and looks like this:


I cropped it and re-sized it 200 x 200, and the quality didn't drop, despite being a smaller size:
 

Brogan

XenForo moderator
Staff member
#6
You're asking the impossible.

When images are made much smaller it is impossible to retain the same resolution.

The difference in resolution, sharpness and quality in the two images in your example above is very clear, despite your claim to the contrary.
 

Amaury

Well-known member
#7
You're asking the impossible.

When images are made much smaller it is impossible to retain the same resolution.

The difference in resolution, sharpness and quality in the two images in your example above is very clear, despite your claim to the contrary.
I have no problem at all with the "No Thanks," but now I'm confused. The quality of the two images above is indeed very clear, as you said. However, you also said that quality is expected to drop when the file size is smaller, so how come in my OP, the thumbnail, which is a smaller size than the full image, is slightly less clear, but in my example above, both the large image and the smaller image are the same quality, despite one being smaller in size?
 

Jeremy

Well-known member
#9
You used a computer program and manually changed the two images, correct? There is a human component. Computers can't just "resize" an image and determine what to take out without losing quality.
 

Amaury

Well-known member
#10
If you think both of those images have the same quality then I suggest a visit to the opticians.
Excuse me? :p

In any case, I can see a slight difference in quality when comparing the 200 x 200 and 1300 x 867, but it's not as noticeable as the images in my OP. I think I figured it out, though: If I insert two images of different sizes as full images, there is a slight noticeable difference in quality -- particularly, sharpness -- but if you insert two images of different or the same sizes as a thumbnail and a full image, then the difference in quality is more noticeable.

You used a computer program and manually changed the two images, correct? There is a human component. Computers can't just "resize" an image and determine what to take out without losing quality.
Not a computer program, but I crop, if necessary, and re-size my avatars on Imgur.
 

Chris D

XenForo developer
Staff member
#11
There's an important thing missing from this experiment.

The resized image is 200 x 200. The attachment thumbnail is about 100 x 50.

So the fair test would be:

upload_2014-2-27_0-38-58.png

So, now, is there a loss of quality?
 

Daniel Hood

Well-known member
#13
I don't absolutely hate the idea of thumbnails being cropped instead of just being made smaller because it could increase the quality of thumbnails but it would be difficult to implement. The system I guess could select the middle most pixels but that's not always the most desired section. You could require manually cropping the images but that'd be a hassle especially if you never planned on using the thumbnail version.
 

Brogan

XenForo moderator
Staff member
#14
I cropped it and re-sized it 200 x 200, and the quality didn't drop, despite being a smaller size:
The difference in resolution, sharpness and quality in the two images in your example above is very clear, despite your claim to the contrary.
but in my example above, both the large image and the smaller image are the same quality, despite one being smaller in size?
Perhaps this will make it clearer?

Your original image:
1.png

Your resized image:
2.png