Understand when the removal button becomes available and how to distinguish loading, invalid files and an active task.
Wait for a valid image preview
The button is disabled until the tool has opened and prepared a supported photo. Choosing a filename is not the same as successfully decoding the image. Read the status if the preview does not appear. The file may be unsupported, too large, corrupted or beyond the pixel limit.
Check whether a task is already running
During processing, ToolNivo disables the remove button and file selector to prevent overlapping work on the same image. Cancel is available if you need to stop. Let the current operation finish or cancel it once; repeatedly tapping a disabled control will not speed it up.
For example, selecting a 40-megapixel photo can fail the pixel limit even if its compressed file occupies less than 15 MB. In that case, prepare a resized copy rather than waiting for a button that cannot become available for that file.
Recover from an unexpected state
If no task is running and a valid original preview still does not enable processing, clear the photo and select it again. If the page remains unresponsive, reopen it in a recent full browser and retry with a small supported file. Refreshing discards the current unsaved result, so download any useful output first. Do not treat the absence of an active button as evidence that your image has been uploaded or queued on a server; processing is local.