Hi, thank you for reaching out and for taking the time to report this issue with such detailed information.

This scenario will be investigated further to see what might be causing the excessive memory usage and whether improvements can be made.

In the meantime, you may consider temporarily downgrading to PhotoShow 4.89.2 (https://addons.mozilla.org/en-US/firefox/addon/photoshow/versions/). It has more limited support for subframes and does not include some of the latest features, but it should also have lower memory usage.

Further updates on the investigation will be posted here. Thanks again for the report, and cheers!

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Edited - 30 July 2026:

Hi, just a quick update. Some investigation has been done into the reported memory usage issue, however, further information is needed to reproduce it. If possible, could you provide a bit more details? Specifically,

- When you mentioned "Firefox sleeping tabs", were you referring to Firefox's built-in "Unload Tab" feature, or a third-party extension or application?

- Roughly how many tabs did you have open in total, including inactive or sleeping ones?

- When you said "activate this add-on", what exactly did that mean? For example, was it enabling PhotoShow from Firefox's Add-ons Manager, or performing some other action?

- What's your PhotoShow version when you had this issue?

If it's more convenient, feel free to share these details via GitHub, the PhotoShow Discord community, or email, where they can be followed up more easily if additional information is needed.

Thanks again for taking the time to report the issue and help improve PhotoShow!

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Edited - 31 July 2026:

Thanks a lot for the details! I'll be digging into it, with further progress being posted here.

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Edited - 15 August 2026:

Hi, just a quick update: PhotoShow 4.91.0 has now been released with several performance improvements, some of which could potentially help with the memory usage you're experiencing. You're very welcome to give the new version a try and see if it makes a difference.

Given your particular use case with a very large number of tabs and windows, if the performance issue still persists, there is also a new "Performance Optimizations" section under PhotoShow Options page → Utilities.

In particular, you can enable "Skip embedded page content (e.g., iframes)" to further reduce PhotoShow's resource usage. This disables the most resource-intensive functionality introduced after version 4.89.2, so it may be especially helpful in your case.

After updating PhotoShow or changing these settings, restarting Firefox is also recommended to ensure the updated extension and configuration take effect as expected.

Thanks again for taking the time to provide such detailed information and help investigate the issue. Please feel free to let me know how 4.91.0 performs with your setup.

Cheers!