Look at the details on the jpeg settings from the image itself.
Subsampling is turned off for some and on for others, which gives the target size far fewer bytes to work with.
This is a common problem with photoshop users, they use the highest settings which turns off subsampling but then reduce the filesize allotment which gives it less room to work with. You get better results if you have a target filesize by turning off subsampling first, which photoshop does not do by default until you drop the quality target very low.
This entire test has to be redone.
Use SUBSAMPLING OFF and PROGRESSIVE ON for all (jpeg) images for the web.
(and do not use default photoshop settings ever for web images)
ps. every time you save a file or image in adobe products it embeds a hidden fingerprint (beyond exif) that identifies your specific install - so not only does it add extra file size, every image you post can be traced on the web - use jpegtran or jpegoptim to strip it
I would be very happy to see a few examples of photograph compressed with the OP method and your method.
It should say SUBSAMPLING ON and PROGRESSIVE ON
Not subsampling off. Off is the incorrect setting and makes much larger images (or reduces the available space when restricting file size).
What you're describing sounds to me like someone recommending Text Edit, Apple Script, and Automator to do Unix commands because they didn't know Terminal was in the Utilities folder.
All the extra stuff you don't like are used by design studios. The metadata keeps track of the color profile, thumbnails, comments, and other metadata commonly used for managing large libraries of images.
When doing "Save For Web" Photoshop disables subsampling for Maximum and High (the default) and also does not enable progressive by default. It also adds meta.
How much of your critique still applies to 'Save for web'?
Nobody (should) be using the normal save dialog for web images so I'm not sure how much of what you say remains valid.
> Some people like interlaced or "progressive" images, which load gradually. The theory behind these formats is that the user can at least look at a fuzzy full-size proxy for the image while all the bits are loading. In practice, the user is forced to look at a fuzzy full-size proxy for the image while all the bits are loading. Is it done? Well, it looks kind of fuzzy. Oh wait, the top of the image seems to be getting a little more detail. Maybe it is done now. It is still kind of fuzzy, though. Maybe the photographer wasn't using a tripod. Oh wait, it seems to be clearing up now ...
But the real reason is it also produces smaller file sizes.
What we did for the non-tech people was simply tell them to always use setting #6 on photoshop and use the progressive setting. Two steps seemed the most they could handle.
http://i.imgur.com/vct3D.png (best one-shot photoshop settings for web jpegs)
I had to go into photoshop and save the same image repeatedly under all the different settings and then examine the resulting jpeg under different tools to see exactly what it was doing.
It also doesn't help that photoshop bloats jpegs by adding hidden adobe meta to every jpeg (beyond and different from exif).
Here is a technical analysis someone did on the photoshop settings:
I believe if you use "Save for Web", it will strip out most metadata and EXIF from the image before saving. Here's a result of using "Save for Web" (1.jpg), passing through JPEGTRAN with `-copy none -optimize` (2.jpg) and `JFIFREMOVE` (3.jpg):
It can also do a lossless conversion to progressive format.
Most people do not know about it though. JPEGOPTIM is another one.
You can examine what's embedded in the image here http://regex.info/exif.cgi
but there are better offline tools.
* It sounds great in theory but the previous example only saved < 200 bytes. That's not really optimization, that's overkill.*
That's a fair point, but if you've got a site that's getting hundreds of thousands or millions of views, or a large number of thumbnails, the one-time effort to shrink image size might be worth it.
Web designers don't "Save" web images, they use "Save for Web" which strips out the extras.
Photoshop won't do 8 bit opacity (as opposed to hard transparency), whereas Fireworks will.