A few tips:
- If you are making money with your pictures, and are seriously concerned about the exact appearance of the pictures on the internet, there really is no excuse for NOT buying a calibration device. Get one, even a cheaper 99 dollar version of the Spider or ColorMonki or something will be better than what you do yourself.
- Second, get a colormanagement aware software package. Now Photoshop CS is probably overkill, so get Photoshop Album.
- Third, after having these things done, start working AdobeRGB colorspace during scanning. This is not that difficult, since most scanners scan to AdobeRGB anyway, or have a setting for that.
- Fourth, now working in AdobeRGB is OK for "home-printing", as it will allow brighter greens than sRGB, but NOT for display on the internet. You need to CONVERT each image from the AdobeRGB colorspace to sRGB. This should be an option in Photoshop Album. Save these as separate images from the originals. In Photoshop CS(1-4), you could do this in batch by choosing "File/Scripts/Image processor."
Currently, your images DO NOT have an included colorspace, as I checked that in Photoshop. This will mean that the images are displayed without guarantees about color rendering, even if the user has a calibrated monitor and colormanaged webbrowser. If you convert to sRGB, you don't have this issue since most monitors approximately match the sRGB colorspace, see the next point, Jeffrey has written a really good article about this.
- Fifth, read this excellent introduction to colormanagement and display of images on the web and why it can go wrong by Jeffrey Friedl, I think it will explain a lot about your issues. It is a seven page blog article, I recommend you to read it all, it will definitely help and he explains things in a understandable way, better than I can do in a short post here:
http://regex.info/blog/photo-tech/color-spaces-page1
- Six: even if you do all this, you should be aware that, even with well calibrated monitors on both computer platforms, there may be a noticeable difference between Apple and Windows machines. This has to do with the way especially older Macs used to be calibrated, which differed from Windows (technical term Gamma, that differed)
The good thing: On my calibrated monitor, most images look fine, maybe the colors a bit oversaturated, but that maybe how you intended it, but it may also be related to not having included the colorspace and converted to sRGB.