Let users raise the tab thumbnail cache limit on Firefox for Android

[Gethwing]

**Let users raise the tab thumbnail cache limit on Firefox for Android**

On Firefox for Android, tab thumbnails live in a fixed-size cache. Once it fills, the oldest entries are evicted. With several hundred tabs open, roughly the most recent hundred have previews in the tab tray and the rest are blank placeholders.

The eviction policy seems backwards for how people actually use the tray. A tab I opened this morning I can identify from its title, or just by scrolling to the top. A tab from three weeks ago is the one where the screenshot is doing real work — often it's the only thing that reminds me what the page was, because the title alone ("Home | Docs", "(4) Reddit") tells me nothing. Recency-based eviction strips previews from exactly the tabs that need them most.

Tab Groups on Android makes this more visible, not less. Groups are designed for tab sets that live for weeks — a trip, a research project, a shopping comparison. That's a supported reason to keep old tabs around, and those are precisely the tabs that lose their previews.

**What I'd like**

A setting under Settings → Tabs for the thumbnail storage budget: Default / 500 MB / 1 GB / No limit. Default unchanged, entirely opt-in.

**Why this looks low-cost**

- The limit is already a single value in the app. Exposing it doesn't need new storage machinery, just a preference read.
- It's disk, not RAM, so raising it doesn't affect memory pressure or performance for anyone who leaves it alone.
- Phones ship with 128–512 GB now. A few hundred MB of thumbnails is a trade heavy tab users would happily make knowingly.
- Delete browsing data → Cached files already clears these, so there's no new privacy surface and no new control needed.

**Smaller versions that would still help**

If a user-facing setting is more than you want to maintain:

- Weight retention by group membership or pinned status rather than pure recency, so tabs the user has deliberately organised keep their previews.
- Store smaller or more compressed thumbnails so more fit in the same budget. A slightly softer preview is far more useful than an empty card.
- Scale the cap to available device storage instead of using one fixed number for a 32 GB phone and a 512 GB one.

Either way, the current behaviour means the tab tray's main visual affordance quietly stops working for anyone past a certain tab count — and those are the users who need tab management the most.

[Jon]

Thanks for submitting an idea to the Mozilla Connect community! Your idea is now open to votes (aka kudos) and comments.

[sahil123]

Yes