Thank you for your responses to my questions. I have checked out the links to websites that you have pointed me to.
After too many years of teaching in rural communities with old computers and dial-up internet connections I do not think my problem is learning how to optimize my website by making the files smaller and quicker to download. Instead my difficult is not knowing my limits now that I am using a new computer and finally have access to much faster internet connection speeds.
In hindsight, in looking at the work I have done on my new website I am realizing that I have probably created far too many directories with only a few files in some of them. In the future, when adding new sections to my website I am thinking that I should try to create fewer directories with more files per directory. I asked question #2 up above because I want to know if there is any sort of maximum number of files per directory that I should be aware of.
I asked question #1 up above mainly because I am not sure how many pictures to include on a page of thumbnails. I have always considered tiny little thumbnails to be useless so my thumbnails tend to be small pictures of 226 x 150 pixels or 300 x 200 pixels. I suspect that many of the visitors to my website will be satisfied just seeing these small pictures and only the most curious will want to proceed to see the full size photo.
In one section of my website I took 40 thumbnails of 300 x 200 pixels and divided them into 5 pages of 7 to 10 thumbnails per page. When watching a relative visit my website I realized that she was getting frustrated with having to find and click on the link to the next page so frequently. In another section of my website I tried taking 27 thumbnails of 226 x 150 pixels and displayed them on a single page. I thought that I was pushing the maximum limits of kilobytes per page until I started wandering around the internet and realized that my page would download and display faster than some of the websites that I visited.
I am currently creating a new section for my website that will have approximately 100 thumbnails of 300 x 200 pixels. I am wondering how many thumbnails I should include on a page. I would like to find the optimum balance between pages that will download and display relatively quickly versus not asking my visitors to find and click on the next page link too often.
I am not sure if it would help but my website is: http://www.packsack.info
The sections of my website that I have referred to are Photographs of Split Lake (40 thumbnail pictures) and Science Experiment: Dissecting a Bird (27 thumbnail pictures).
I would appreciate any advice and suggestions you may have.