Might have something to do with interlace?

I don't have Photoshop on this computer, so I can't check it for myself, but is it possible that the photo is in CMYK -- and that PS automatically converts it to RGB when you "save for web" but leaves it as a CMYK when you merely "save as" jpg?

CMYK - Hadn't thought of that. Yes, it was created as 300 DPI, CMYK, 8 bit. It is primarily going to see print use in a number of small trade 'magazines' (of quite modest print quality:((, so I created as CMYK knowing that I could later save in several formats; convert the color mode to RGB and such. That may be the reason.?

Still seems odd that I can 'save as' .jpg and see it in the directory - but not drop it in .html or .pdf. It does drop in .doc though. Hmmm. That might be the reason though.

In the end, I only care about my master .psd, and providing a final version ready for print along with needed alternatives. That is, it will also be used for for PDF presentation for people that don't get hard copies of the publications, and probably will be dropped into several websites for the same reason. I have already planned, once the comps are approved to convert a copy of the master file to RGB and lower the file size as much as possible for those applications. For the print people, I will probably provide the highest possible quality no-layer .tif, no-layer .psd, and DCS 2.0 .eps. This practice has always covered everything that anybody could possibly want:)) That .eps conversion really skyrockets the file size, but no matter.

I only ran into the 'problem' while knocking out some quick comps to send off for okay on content and layout.

From Matt Cutt's site:

You got an JPEG which uses CMYK instead of RGB encoding, and Firefox/IE choke on such files. In Photoshop, you can convert the JPGs to RGB colorspace, or you can select “Save For Web…” to make the file valid for common browsers.

Very interesting. It was a quick knockout on saving a variety of files, so that is how I ran into this (for me) new twist. Obviously, there would usually be no point to take a print ready CMYK .psd and 'save as' a .jpg. Usually I would 'save for web', knocking down the dimensions and quality, then drop in a .pdf so everyone would have a copy with which to provide input. When I ran into trouble this is exactly what I went back to. I accidentally learned something new here.

Interesting to know that IF I want to provide the highest possible quality .jpg that I MUST convert to RGB before 'save as'. Makes sense, and if needed, probably would have wound up going that route without undestanding that it was required:))

The final presented versions of this will be a no-layer .psd, a very high quality .jpg (converted to RGB color mode FIRST:)), and a .jpg sized and optimized for web use.

Very helpful answers. Thanks to all.

Thanks for letting us know what you figured out. I like that much better than when a thread leaves things hanging without a solution.