Here's something more complex to resolve, put in lowest JPEG (iPhoto)
and nearly at the limit (96kb), 888 pixels long dimension.
Dan sent me the 3 MB original jpeg of his lobster pot photo which he resized and compressed with Mac iPhoto to 888x590 and 96 kB to upload for the quoted post.
I used the Save for Web ... (Plugin) function of the file menu of the IrfanView app for Windows on Windows 7 to produce another 888x590 and 98 kB version of this photo.
I attach it.
There are other paths through Irfanview to resize and compress this photo. None of them produces quality this good except using Save for Web of the File menu for
both resizing and compressing in a single invocation of Save for Web.
Open this attachment and the one from Dan's post,
http://igkt.net/sm/index.php?topic=2892.msg17361#msg17361, in different windows for simultaneous viewing to compare the quality of the iPhoto and IrfanView processing of the image.
I cannot detect a difference of quality between these reduced photos. I
do see a big difference of quality between the reduced photos and the original photo (3008 x 2000 pixels x 24 bits/pixel, 2.87 MB). Much more fine detail is visible in the original. For example, it is easy to see at a glance that a simple overhand knot forms the loop in the bridal on each pot to which the surface line is fastened by a double becket bend. In the reductions, we feel the need to compare and contrast several of the examples in the photo before reaching this conclusion.
This knots-in-the-wild photo may be typical of the documentation requirements of such knot photography, but close-up studio photography of knots on a table top is much less demanding of resolution. Such photographs typically provide a sense of detail and reality even in an image size of 400 pixels wide with a file size of 30 kB or less.
David