Changing quality setting for image size

[mjm]

At one of my galleries I'm considering raising the quality setting from the default setting currently at 70

1) Is Scan database the only way to do this?
I tried it in a category at it took quite a while to process.
Scan Database
> Rebuild all thumbnails.
> Rebuild all medium images.

2) Is there a way to rebuild large images?

3) I'm using GD2, and as I'm not using watermark feature, would ImagMagik produce clearer pics?

Thanks,
Mark

[Chuck S]

Hello

You can not rebuild large images. That is the image that everything else is used to rebuild from. The way you raise and rescan images is as you have correctly laid out.

[mjm]

Okay, I see the confusing part of it...
Here's an example
Max allowable image width in pixels - 1024
Max allowable image height in pixels - 768

Trigger medium graphic height and width - 450

Original upload - 137.9K

At 70 setting: medium= 24.0 ; large = 82.0

Scan db > Rebuild medium images >

At 100 setting: medium= 137.9 ; large = 82.0

I was hoping that the medium pic K value would increase relative to 450 trigger.

The main purpose of having the medium set at 450 is to make viewing easier for dial-ups.
Unfortunately the jump from 24.0 (70 setting)to 137.9(100setting) for medium makes it larger K than the view large option

[Chuck S]

thats what happens when you want no compression

[mjm]

It would be better if the medium was riased relative to the
Trigger medium graphic height and width

As it functions now I am no longer able increase the quality settings relative to previous settings and get a decent ratio between medium and large image K value.

Should I post this into Suggestions or do you think there is no workaround?

[Chuck S]

Hello

Quality on a higher level means no compression hense the file will be bigger. Things are sized based on how you say. If you set it to 70 and its 30K okay and at 100 no compression its say 120k thats absolutely normal

[mjm]

i Chuck, I'm leaving the quality setting at default 70 till I can understand more about this stuff.

I tried uploading several pics at 100 quality setting, then reduced the setting at 10 increments ... results shown below.


Upload photo settings
Max allowable image width in pixels - 1024
Max allowable image height in pixels - 768
Trigger medium graphic height and width - 450
Max upload per pic 300K

Photo A: Original size - 132K ; Pixels - W 1024 X H 768
Quality setting 100: Med - 116.4 ; Large - 131.0K
Quality setting 90: Med - 37.8K
Quality setting 80: Med - 25.3
Quality setting 70: Med - 20.2

Photo B: Original size - 228K ; Pixels - W 768 X H 1024
Quality setting 100: Med - 185.4 ; Large - 500.8K
Quality setting 90: Med - 72.9K
Quality setting 80: Med - 49.7K
Quality setting 70: Med - 39.5

Photo C: Original size - 100K Pixels - W 640 X H 800
Quality setting 100: Med - 205.2 ; Large - 97.5K
Quality setting 90: Med - 87.3K
Quality setting 80: Med - 62.5K
Quality setting 70: Med - 50.6K

Note increase of large image size of Photo B
... way above the 300 max upload size per pic

- If I had initially had the setting at 100 for all pics in the gallery, as it stands, I would not have a way to readjust this K value to a smaller size.

Anyway .. just thought I'd let you know of the quirky nature of quality setting relative to initial pixels allowable and trigger size.

with hopes that this can be more fine-tunable in the future.

Mark

[Chuck S]

It would appear to depend on the individual picture.

Only the large size on b looks outside the range of what I would say normal but it could depend on the initial photos compression and how it was saved originally.

[mjm]

Re: Photo B
This happens to pics displayed in the vertical format - H1024 X W 768

when the upload setting is at ...
Max allowable image width in pixels - 1024
Max allowable image height in pixels - 768

I tried both Photoshop Elements, my standard method of resizing and Preview with same results.
In this situation my only need to use the above was to rotate the original pic from horizontal W1024 X H768 to vertical W768 X H1024