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Testing Ken's Helpful Information - Image Resizer v's Paint

Posted: May 15th, 2017, 4:56 pm
by Kevin
Thanks Ken for your recent information regarding resizing images.

Below is just a test.
Both images were selected to be @ 854 pixels horizontal.

What i'd like to know is how images can be significantly enlarged by using the sometimes enabled icon on the attached image.
Sometimes this feature is enable within the image and sometimes not - Why?
Also, when it is enabled, no matter what size the image is, at times (i suppose it depends on the initial software when resizing) the image can be enlarged significantly, enabling a very good close-up of the entire tree.

Original Image @ 6059 x 4044 pixels

First image via 'Image Resizer' @ 719 x 480 pixels
_DSC1777-2 (Small).jpg
Second image via 'Paint' @ 854 x 569 pixels
_DSC1777-2 - Paint.jpg
Kevin

Re: Testing Ken's Helpful Information - Image Resizer v's Paint

Posted: May 15th, 2017, 5:03 pm
by Kevin
Well,

The quality of the resize is significantly better with 'Paint' @ 131KB compared to 'Image Resizer' @ 89KB.

But neither image enabled the enlargement icon within the attachment - Why?

As i mentioned - just testing.

Kevin

Re: Testing Ken's Helpful Information - Image Resizer v's Paint

Posted: May 15th, 2017, 6:23 pm
by melbrackstone
The forum software creates a large thumbnail in each post, which, when attached using the proper procedure, is then able to be enlarged to the size you made them by clicking on the image.

When clicking on the image it's very clear the Paint version is larger and has more detail.

Re: Testing Ken's Helpful Information - Image Resizer v's Paint

Posted: May 16th, 2017, 3:06 pm
by kcpoole
Interesting comparison
The difference i assume will be in the amount of compression applied to the final file, or the algorithm used to do the resise.

Not sure if either is tuneable though

Sent from my SM-G800Y using Tapatalk

Re: Testing Ken's Helpful Information - Image Resizer v's Paint

Posted: May 16th, 2017, 6:30 pm
by kcpoole
melbrackstone wrote:The forum software creates a large thumbnail in each post, which, when attached using the proper procedure, is then able to be enlarged to the size you made them by clicking on the image.

When clicking on the image it's very clear the Paint version is larger and has more detail.
Ok now at home on a decent PC to check, The images are slightly different resolutions with the paint one being slightly larger, 854 × 569 pixels (134.2 kB) vs 719 × 480 pixels (91.2 kB)
The issue will be the different compression ratios between the 2 products. Teh effct is the loss of definition in the centre part of the flower.

JPG is a lossy compression format and is adjustable to between 0% and 100% ( zero being the worst quality, 100% being no compression)
Typically software defaults to somewhere between 70% and 85% and usually can be adjusted.
The other thing is that every time you resize a JPG, it gets compressed again so is a multiplying effect and thus loss of quality and definition each time.

Your camera will compress its JPG, the resize will do again and each time lose quality depending on how much you compress,
if you want to avoid one step, Save from the camera in RAW or TIFF. these are Lossless formats.
I typically save in JPG on the camera but any editing on the PC I use GIMP and save at 100% so avoid the loss of quality there. When I resize for posting I do at 800x600 and 85% compression (on Linux).

Ps, from within the saved JPG, you cannot find out what level of compression is already used. That data is lost when saving.

Ken
Ken

Re: Testing Ken's Helpful Information - Image Resizer v's Paint

Posted: May 17th, 2017, 3:56 pm
by Kevin
Hello Ken,

Firstly, i hope i haven't broken any rules or offended any member by replicating the below 2 images - if so please advise and delete.

In the original posting of the below 2 images, both images, once opened, enabled the enlargement icon within the image and when enlarged was selected, the close up view of the tree was very impressive.

In this test, i don't know if downloading and uploading will affect the original posting image details, hence the test.

Steven's image was 888KB and Wal's was only 341KB, but both images after opening the thumbnail, the image enlarge icon was enabled and the close-up shot was very large.

Hopefully recreated below.
Sick Maple 1.jpg
Koji Hiramatsu 2.jpg
It appears to have worked - am i making sense and i'm not too sure if you can see what i'm seeing either.

Steven has appeared to master this enlargement technique and whatever technique employed by Wal was equally successful regardless of the original size of the uploaded image.

Not too sure if i'm making sense with my question - What technique when resizing and uploading images enables the opened thumbnail to be so enlarged, when selecting the enlarge icon on the image (as in the example images provided above) to enable an impressive inspection of the posted tree?

The reason why i ask is being able to upload relatively small files that can then be significantly enlarged to help members view / inspect / diagnose each image. Helping both the original poster and viewers answers.

Thanks,
Kevin
(EDIT) Just an afterthought, i haven't completely read through the AusBonsai Photography Forum recently and if this question or answer already exists, i apologise and just point me in the right direction rather than recreate a reply, Thanks Kevin