I have a little over 23,000 image files. I built a simple slideshow screensaver on the Mac (OS X 10.15.4) and it works fine, although it complained about the size of the resulting screensaver after the build (~6GB). When I tried to use my original files iScreensaver crashed (crash dump on request), although these were unmodified files size-wise. So I resized all of my photos to max 1024x768 and adjusted JPEG compression to 80% which seemed to work.
When I moved over to the PC (Windows 10 Pro version 1909) and tried to build, the build finished with errors, complaining again about the resulting screensaver size and said there was a size limit of 4GB. That sounds suspiciously like a 32-bit limitation. I really don’t want to cut my image size down further and I’m not going to limit the number of images (in fact, that may grow). I’m not sure using a tighter JPEG compression will help much either. I’d really like to build on the PC for the Mac since the PC is where all of my images reside.
Is there any way to get iScreensaver to fetch, resize, and display images from a local folder (with subfolders) rather than producing a gigantic executable? Thanks for any guidance you can provide.
Great question - as you’ve discovered, the windows build is a 32 bit app - we do this for maximum compatibility becuase 32 bit SCR files can run on either 32 or 64 bit versions of Windows. Unfortunately, that does put a hard 4GB filesize limit.
With 23000 images, that leaves about 150KB per image. JPEG often gives OK performance at a 10 to 1 compression ratio, which is similar to your 1024x768 image size.
iScreensaver uses the built-in OS JPEG compression routines which are good, but you may be able to do better - there are some specialized tools which can do an extra good JPEG compression. So you might be able to pre-compress them ahead of time using one of these tools to gain a few extra % of size reduction:
Unfortuantely, there’s no way for iScreensaver to function like you want (pulling images in real time from another location), so you’ll have to live with the 4GB limitation on Windows.
I have a little over 23,000 image files. I built a simple slideshow screensaver on the Mac (OS X 10.15.4) and it works fine, although it complained about the size of the resulting screensaver after the build (~6GB). When I tried to use my original files iScreensaver crashed (crash dump on request),
Yes - please email your crash log(s) to support@iscreenaver.com and we’ll take a look.
Crash dumps sent. Thanks for the compression link. Is there a size limit for screensavers on the Mac? If not, I’ll just continue building there.
Our screensavers built for the Mac are truly 64-bit apps, so there are no hard limits. As with any software, there are likely to be some performance issues if you are trying to include tens of thousands of images, but this will depend a lot on the capabilities & performance of your individual mac (RAM, Disk/SSD speed, graphics card, etc).
There isn’t any way to have 32-bit and 64-bit build options for Windows? Just askin’.
Not possible, sorry. On windows the executable is 32 bits - a major benefit of this is that it’s delieverd as a single file (so you don’t have to worry about DLL files and library folders etc.) But, as you’ve discovered, there is a 4GB limitation.
Out of curiosity, why so many images? Perhaps if you can explain how you are using the software we could theorize about other solutions.
This is just a simple slideshow that we run on my wife’s Mac and watch during mealtimes. The photos are all family pictures that span 1880-2020. Of course we could subset the pictures, but what fun is that? 
You know what we find the most valuable with iScreensaver? The fact that we can GO BACK to pictures that we missed earlier. Just FYI, we used to use ArtSaver as that allowed simply pointing to our photo repository and it also provided going back and forth in the slideshow stream. But as of Catalina ArtSaver broke, ostensibly because of screensaver sandboxing requirements.
Thank you for reporting these issues to us.
We are happy to announce the release of version 6.5.0.1330 which has major improvements for working with giant projects. (It does not, however change the 4GB limitation on Windows builds).
See Release Notes for details.