GIMP's Pencil intentionally produces hard edges and does not apply anti-aliasing, even when the selected brush looks soft. Changing the tip alone will not make it behave like Paintbrush. For a photographic correction that needs a gradual transition, compare the two tools before smoothing the whole image or exporting a larger file.
Confirm the tool, not just its icon preview
The brush thumbnail describes a resource used by the tool. It does not guarantee that every tool interprets its edge in the same way. A retoucher can select a fuzzy circular brush, overlook that Pencil is active, and conclude that the photograph or tablet has lost soft edges. Read the tool name in the options rather than judging the brush preview.
Hard edges can be valuable when editing tiny icons or deliberate pixel artwork, where each pixel needs a clear decision. The same behavior can be distracting on a cheek, a smooth product surface, or the boundary of a broad local color adjustment. The task determines whether the crisp edge is helpful; there is no need to label Pencil universally inferior.
Compare two marks on a disposable layer
This is a reader test plan and has not been executed here. Duplicate the image and add an empty test layer above it. Select one round, visibly soft brush resource and keep its displayed size and color unchanged. Make a short diagonal stroke using Pencil. Next make a comparable stroke using Paintbrush, checking each tool's own options instead of assuming that all settings carry over.
Inspect the edge at high zoom to understand the pixels, then return to the intended viewing size. Record whether the transition is abrupt or gradual and whether the mark suits the repair. The exercise is not a contest for the smoothest possible line; it asks which edge behavior belongs in this particular photograph.
Do not blur a whole photo to hide one tool choice
If a small correction was painted with the wrong tool, undo that correction or restore its separate layer. A global blur can conceal the edge while also removing eyelashes, fabric fibers, and printed label detail. Increasing output dimensions cannot recover those details or change the reason the mark had a hard boundary.
For intentional pixel-style art, preserve the hard decision and evaluate the grid separately. For a photographic repair, redo only the affected area with an appropriate edge and inspect it against the unmodified source. Avoid tracing every hair with a softened brush when the original hair already exists and only a small color correction was requested.
An Imagild style reference should be free of accidental diagnostic marks and localized tool artifacts. Export a separate copy, reopen it, and check that the corrected region joins the surrounding photo without a visible painted rim. This workflow explains desktop GIMP's Pencil behavior; it does not claim that Imagild offers the same tool names or brush engine.