The instruction you need depends on what you want to change: upload a separate cover image, or pick a frame from the Short. Those are different editing routes. Following a phone tutorial while looking for a desktop upload button makes an already confusing task harder.
YouTube's current custom-thumbnail instructions document uploading a separate Shorts image in desktop Studio. Its Shorts creation guide describes selecting a video frame in the YouTube mobile app. The steps below follow those two routes, checked on September 24, 2026.
YouTube Shorts thumbnail size
For a custom Shorts image, YouTube currently recommends 2160 × 3840 pixels, at 9:16, with a minimum height of 640 pixels. Use JPG or PNG. The documented desktop upload limit is 50 MB. These are the current Shorts-specific recommendations, not the landscape dimensions for long-form video.
A 1080 × 1920 canvas has the same shape; it is half the recommended width and height. If that is your existing design, keep its proportions when working on a larger version. Enlarging a small, blurry image will not restore missing detail.
Choose the canvas before arranging text. For example, a cooking Short could use a close view of the finished dish with its name beside it. Shrinking an entire landscape recipe graphic into a portrait canvas would leave the ingredients and instructions competing for space.
If your artwork needs a different canvas, Solnk's image resizer can help with the sizing step. Read the result at a small display size before using it: a valid file can still have an unreadable title.
Upload a separate image on desktop
Uploading a separate image for a Short is currently available only in desktop YouTube Studio. Your account must be verified:
- Open Content, then the Shorts tab.
- Open the Short's editing page.
- Under Thumbnail, choose Upload file.
- Select your cover image and click Save.
YouTube notes that thumbnail changes may take time to appear. See its desktop instructions for the current controls.
Keep the exported cover alongside its source design and the video. Use a shared filename, such as pasta-short-03, so a teammate can identify the matching assets without reopening every file. That small piece of organization matters when several Shorts use similar footage.
Select or change a frame on your phone
For frame selection, use the YouTube app, rather than the Studio app. YouTube's mobile guide supports selecting a frame before or after upload.
Before publishing, record your Short, reach the final upload screen, tap the thumbnail's edit control, select a frame, and tap Done.
For an uploaded Short:
- Open the YouTube app and go to your channel's Your videos.
- Open the Short's More menu, then Edit.
- Select the frame you want and tap Done.
You can also add text and filters to the selected frame. Review those changes before finishing: YouTube warns that you cannot return to previous edits afterward. This editing limitation does not change its guidance that you can select a frame after upload.
Selecting a frame is different from uploading a separate JPG or PNG on desktop. Decide which result you need before switching devices.
When the thumbnail option is missing
Check the editing route first. If you have prepared a separate image, return to the documented desktop upload path. If you want a frame already inside the video, follow the mobile frame-selection path.
Check channel verification next. YouTube lists custom thumbnails among the features unlocked by phone verification. This is not the public verification badge beside a channel name. Confirm which channel you are editing before troubleshooting its eligibility.
If the correct route and verification still leave you without the control, record the device, app or browser, channel, and exact screen before contacting YouTube support. Those details describe a reproducible problem. Repeatedly exporting the same picture does not tell you why an upload control is absent.
Avoid deleting and re-uploading a published Short merely to look for a missing thumbnail option. That would turn a cover-editing problem into a new publishing decision without first establishing the cause.
Keep the cover task separate from publishing
A platform's native editor and a scheduling service do not necessarily expose the same controls. For example, Buffer's YouTube Shorts documentation says it does not currently support selecting a custom Shorts thumbnail. That describes Buffer's integration, not every operation available in YouTube Studio.
Treat the upload destination as part of your asset handoff: video, cover file, and where the cover must be applied. If you use Solnk for YouTube scheduling, verify the cover on the actual YouTube video rather than assuming a scheduling preview proves the final result.