Assume the file was saved. The X on an uploading tile takes the tile off your screen, and it tells you Upload cancelled, but it does not stop the transfer that is already running. The file finishes uploading in the background and appears in your project a moment later.
So the honest answer to "did anything get saved" is yes, almost always. Treat the X as hiding the progress tile rather than as a stop button.
What actually stops an upload
Two things do:
- Leaving the editor. Navigating to another page in the builder, or closing the tab, drops the connection and the upload dies with it.
- Reloading the page. Same effect, and it is the quickest way to be certain.
A partial upload that is cut off this way is discarded. Nothing half-written lands in your project, because the server only creates the image once the whole file has arrived.
If the file did land, delete it from the gallery
Deleting is the reliable way to undo an upload you did not want. Open the gallery, use the bin on the tile, and confirm. Unlike the cancel button, that one asks first and does what it says. Bear in mind a deleted image leaves every earlier version of the project as well, so do not delete something you may want back: see Deleting the cover image.
A cancelled video still counts against your daily allowance for an hour
Video works differently from images. The moment you pick a video, UNI reserves a place for it before any of the file is sent, because the file goes straight to storage rather than through the site.
If you cancel or reload before the upload finishes, that reservation is left behind. It keeps counting against your videos-per-day allowance for one hour, then stops counting on its own. You do not need to do anything, and you do not need to contact support: wait out the hour, or use one of your remaining slots. Video uploads: daily limits, length and format has the allowance for each membership.
A video that did finish uploading is a different matter. It is in your project and it starts processing, so remove it from the gallery if you did not want it.
Uploading several images at once
Images upload one after another rather than all together, so pressing X on a tile further down the queue does not prevent that file from starting later. If you picked the wrong folder entirely, reload the page: it is faster than clearing tiles one by one.