When a tool feels slow: three things to check
If a tool is taking longer than you expect, the cause is usually one of these.
1. The input is much larger than it looks. A 40 MB PDF is 40 MB of parsing. A 12-megapixel photo becomes a ~48 MB canvas. Check the file size first, then the per-item settings.
2. Resolution or quality is set higher than needed. Doubling the render scale quadruples the pixel count. For a quick visual check, 1x is enough; reserve 2x–3x for output you intend to keep.
3. The run is doing more items than you think. A page range of 1-80 at 3x renders eighty full-size canvases. The progress indicator tells you which item it is on, so watching it for a few seconds usually identifies the culprit.
If none of these apply and the tab is genuinely frozen, that is a bug worth reporting — include the file type and approximate size.