Trouble with photo color when saving an image for web

If you convert the file to sRGB it should display roughly correctly even without color management. However, this old rule of thumb only applies to standard monitors, which have a native response reasonably close to sRGB already. If you are using a wide gamut monitor (like e.g. a recent Apple display), this no longer applies. Here you need a fully color managed web browser, and you need to make sure the file has an embedded color profile. Save For Web and Export both strip the file's embedded icc profile by default. You need to check "embed profile" manually.

You also need to have a valid monitor profile, preferably one made by a calibrator.

Failing this, it will look oversaturated.

Proofing to Internet Standard doesn't tell you anything. It just discards the embedded profile and assigns sRGB instead. It's a completely meaningless setting - the only justification is to check whether you've remembered to convert. It doesn't tell you how it will ultimately look.

Thank you! This helped!

By Photo-Color do you mean Pro-Photo RGB? Using that colorspace will look good in Photoshop even though on the very best of monitors you will not see all the colors. This is because Photoshop is a color managed application as is Lightroom and these applications correctly render the colors in the image up to the screens maximum capability. Web browsers with the exception of Firefox., I think, lack color management and render images for the sRGB colorspace, therefore a Pro-Photo image will experience color shifting. The only solution is to use an sRGB color profile embedded into your images to be uploaded to the web. Photoshop can accurately convert between profiles using the 'Convert to Profile' command under the 'Edit' menu and on saving the image there is an embed option for color profile in the 'Save' dialog box..