This is about compression of jpg images and uses this [non compressed] high quality image as an example

It comes from michaelkdickson.com who is a "serious photographer" with more expensive cameras than bin Laden has wives. But beware if you have bandwidth limits as Michael seems to use no compression at all.

Now even though this topic comes under the JAlbum tag, the content is about compression in general. JAlbum has its own options to automatically resize and compress etc [and I am no authority on that]. So please consider the advice here as covering the situation where you ask JAlbum etc to process images that you have already edited yourself.

In my case I use Paint Shop Pro [PSP] as my image editor, and specifically ver 8. In general, the more expensive editors like PSP will allow you vary the compression but will have a default of 85% [ie 15% compression], whereas the freeware ones may simply save at say 85% but neither tell you or offer options.

The idea of the slide show is for you to judge the QUALITY yourself while flipping between the slides, but having access to a central graph [in Excel4] to show you the relationship between compression and file size, which you will see is exponential. I think you will also see that 85% gives a reduction in file size to one quarter of the original, but [subject to your eyes being the judge] with virtually no reduction in quality

Also the slide show demonstates the long standing rule of jpg for photos and gif [as per image above] for graphs, maps etc

Here is the slide show Compression slide show

And here is a MM slide show

As MM freaks know, displaying a "still" photo [but in fact 25 times a second, so it is NOT still] poses other "strengths & weaknesses" [to borrow from the marketing term SWOT]. A jpg saved at say 70% somehow looks BETTER than the original, but a gif goes all nasty as those who have tried to use it for PowerPoint, Excel presentations have found.

I have added numbers at the bottom to show progress of the 5 second slides, and my eyes say that the 100 is maybe not as good as the orig [repeated above the movie] but the quality virtually stays the same until you get to say 60, while the graph in the middle goes from bad to worse

You will also notice that MM has done some "brightening" akin to the PSP One Stop Enhance in the other slide show, so please take that into account as you compare the two below

And to complete the picture, here is the custom profile I made to display the movie, ie at the exact same size but with audio at the minimum possible. But don't be afraid to double click and watch at full screen, as it still looks good