Murder Mystery 2
Free Roblox thumbnail tester
Roblox Thumbnail Tester
Your thumbnail never competes alone. Drop it into a real home grid and watch whether it survives the scroll — surrounded by 36 experiences that were actually trending on Roblox.
Choose an image
Your thumbnail
Device
Format
Runs entirely in your browser. Your image is never uploaded, stored, or seen by us.
Roblox thumbnail preview
DesktopThumbnail 16:9
![[💲]+1 Speed Keyboard Escape | Candy & Chocolate](https://cdn.thumbblox.com/demo/9584852943.webp)
[💲]+1 Speed Keyboard Escape | Candy & Chocolate
Add your imageYours
Your Experience
![Anime Expeditions [UPDATE 😈]](https://cdn.thumbblox.com/demo/7613921865.webp)
Anime Expeditions [UPDATE 😈]
Tower of Hell
![[RIA26] The Block](https://cdn.thumbblox.com/demo/8292068736.webp)
[RIA26] The Block
![BedWars [🎃 JACK]](https://cdn.thumbblox.com/demo/2619619496.webp)
BedWars [🎃 JACK]
![[🍯] Unbox ASMR!](https://cdn.thumbblox.com/demo/10454554751.webp)
[🍯] Unbox ASMR!
Death Order: Simon Says
![[LAMBORGHINI UPD] Driving Empire🏎️ Car Racing📦RP](https://cdn.thumbblox.com/demo/1202096104.webp)
[LAMBORGHINI UPD] Driving Empire🏎️ Car Racing📦RP
![[UPD💣] Drift Tag](https://cdn.thumbblox.com/demo/8420907710.webp)
[UPD💣] Drift Tag
![Shindo Life [249]](https://cdn.thumbblox.com/demo/1511883870.webp)
Shindo Life [249]
How to test a Roblox thumbnail before you publish
Four steps, about thirty seconds. No account, no plugin, no Studio.
Drop in the image
Use the exact file you plan to upload to Roblox — same crop, same text, same resolution. Testing a different export tells you nothing.
Type the experience name
The name sits directly under the image on Roblox and competes with it for attention. A thumbnail that only works without its title is not finished.
Look at mobile first
Most Roblox sessions are on phones, where your card is roughly a thumbnail-sized rectangle. Switch to mobile and see what is still legible.
Shuffle the neighbours
Standing out beside one set of games is luck. Reshuffle a few times — if it disappears against half the grids, it will disappear on the real one.
What a thumbnail has to survive
The grid is a brutal filter. These are the four failures the preview exposes fastest.
It goes muddy next to bright cards
Roblox trending art is loud and saturated. A tasteful, low-contrast scene reads as a dead slot. If your card is the dim one in the row, raise the contrast of the subject, not the whole image.
There is no single subject
At card size the eye gets one object, not a composition. If a player cannot say what is happening in half a second, crop tighter until they can.
The text stops being text
Wording that reads fine at full size turns to grey mush on mobile. Switch to mobile and if you cannot read it at arm's length, cut the words down or make them far bigger.
It bleeds into its neighbours
Cards sit edge to edge with almost no gap. A thumbnail whose border matches the surrounding art loses its shape entirely — give the frame its own value break.
Where your Roblox thumbnail actually has to work
One image, four very different frames. This tester reproduces the harshest of them, but it helps to know what the other three do to your art.
Home recommendations
Roblox moved Home to large 16:9 tiles across mobile, web, and desktop in April 2025, and removed the concurrent player count from those tiles in the same change. Your image and your experience name are the entire pitch. This is the surface the Roblox thumbnail preview above reproduces.
Search results
Roblox later brought 16:9 thumbnails to search results as well. The crop that fails on Home fails again here, which means one Roblox thumbnail test covers both of your biggest discovery surfaces at once.
The experience page
You can feature up to 10 images or videos on a single experience page, and the player count Home hides is still shown here. The first slot carries the most weight, and an approved gameplay video takes that slot ahead of your images.
The square icon
Your 1:1 icon is a separate upload and a separate judgement call. Switch the preview to Icon 1:1 and it swaps to square neighbours, so you are looking at the real comparison instead of inferring it from the 16:9 crop.
What this Roblox thumbnail tester assumes about your file
A Roblox thumbnail preview is only honest if the file you drop in is the file Roblox will receive. The numbers below are the platform's, not ours.
- 16:9, ideally 1920x1080
- Roblox's own guidance is that an experience thumbnail should be 16:9 and ideally 1920x1080 pixels so it always displays in high resolution across the site and the app. Test a smaller export and you will miss the softness that large Home tiles introduce.
- Export the file you will publish
- Roblox accepts .jpg, .gif, .png, .tga, and .bmp. This tester reads PNG, JPG, and WebP, so a PNG or JPG export lets you preview the identical file rather than a stand-in that hides compression artefacts.
- Ten slots, not one
- An experience page can feature up to 10 images or videos. That is why the useful habit is testing per image instead of testing once: every slot you activate is an impression budget you are spending.
- Video leaves gaps a still has to cover
- Xbox, PlayStation, and VR headsets do not currently support video thumbnails. A slice of your audience sees your static image no matter how good the trailer is, so the image is the thing worth testing.
- Moderation is the last gate
- Every upload is reviewed against the Roblox Community Rules before it goes public. Original characters and original assets pass; copyrighted characters and misleading imagery are rejected. A thumbnail that wins the preview and fails moderation is still a loss.
Preview first, then let Roblox run the real test
Roblox already ships a measurement tool, and this page is not a replacement for it. The two do different jobs, in a specific order.
How Roblox's own thumbnail testing works
Thumbnail personalization shows each of your activated thumbnails to a random set of users, measures the qualified play through rate for each group, then pushes more impressions toward whichever image wins that group while still spending a little traffic exploring the others. It is a live measurement on real players, not a judgement call.
Why creators bother
Across Roblox's own test period, experiences using thumbnail personalization saw an average +8.5% qualified play through rate, and some saw increases of +50%. There is one hard prerequisite: personalization does not start until you activate two or more thumbnails. A single image leaves nothing to personalise.
Where the preview fits
Roblox tells you which of your images wins with real players, but only after you publish and only if you have the traffic to reach significance. This Roblox thumbnail tester tells you in a few seconds, before you spend a slot, whether an image is even in the running. Preview every candidate, cut the ones that vanish into the grid, activate the survivors, and let personalization pick the winner from a shortlist that already earned its place.
Thumbnail did not survive the grid?
Describe the moment players should not scroll past and generate a fresh 1920×1080 Roblox thumbnail built to hold its own in that row.
Roblox thumbnail tester FAQ
The things creators ask before they trust a preview.
Is this Roblox thumbnail tester free?
Yes, completely. There is no account, no credit, no watermark, and no limit on how many thumbnails you test. It costs us nothing to run because the preview happens inside your browser.
Does my thumbnail get uploaded anywhere?
No. The image is read locally by your browser and drawn straight into the Roblox thumbnail preview. It never reaches our servers, so there is nothing for us to store, log, or train on. Close the tab and it is gone.
What size should the image be for an accurate test?
Test the file you will actually publish. Roblox's own guidance is 16:9 and ideally 1920x1080 for an experience thumbnail, and square at a minimum of 512x512 for an icon. Running a scaled-down export through a Roblox thumbnail preview tool hides exactly the softness and text breakdown it is meant to catch.
Which file formats can I test?
PNG, JPG, and WebP, up to 10 MB. Roblox itself accepts .jpg, .gif, .png, .tga, and .bmp, so exporting the PNG or JPG you actually intend to upload lets you test the real file instead of an approximation.
Can I test a Roblox game icon as well?
Yes. Switch the format to Icon 1:1 and the preview swaps to the square-icon layout with square neighbours, which is how your experience appears in search and on your game page.
How many thumbnails should I test before publishing?
At least two, because Roblox's thumbnail personalization does not begin until you activate two or more. Preview each candidate here first. Activating a slot with an image that disappears into the grid spends real impressions learning something this preview would have told you for free.
Why do the preview tiles not show a player count?
Because Home no longer does. When Roblox moved Home to larger 16:9 tiles it stopped displaying concurrent players on them; the count now lives on the experience page instead. Switch to Icon 1:1 and the preview does show counts, which matches the surfaces where they survived.
Can I test a video thumbnail?
Not the video itself, and you should still test a still. Xbox, PlayStation, and VR headsets do not currently support video thumbnails, so the static image behind your trailer is what a real share of your audience sees. That image is exactly what this tool is for.
How realistic is the neighbour grid?
The names, art, and player numbers come from a snapshot of experiences that were genuinely trending on Roblox, copied to our own servers rather than hot-linked. It is a snapshot instead of a live feed on purpose: you want a stable, representative wall of competition to judge against, not a target that shifts between two reshuffles.
Is this the same as Roblox's built-in thumbnail A/B testing?
No, and they solve different halves of the problem. Roblox's A/B test measures real players after you publish, which takes days and needs traffic. This preview is the check you run beforehand, so you never spend a test slot on art that was never going to compete.
My thumbnail failed the test — what now?
Work down the checklist above before you redraw anything; most failures are contrast or crop, not concept. If the art itself is the problem, our generator writes a new 16:9 thumbnail from a one-sentence description of your experience.