Is every rotation on this page lossless?

No. Only rewriting the orientation field is byte-preserving for the compressed image data. Baking a turn into the pixels decodes and re-encodes the JPEG and is therefore a new lossy generation.

When is tag rewrite the correct repair?

When the stored pixels are already upright but the orientation field tells compliant viewers to turn or mirror them. The inspector describes the field before offering either repair.

Why is the embedded thumbnail unlinked?

A stale EXIF thumbnail can keep showing the old direction after the full image is repaired. Unlinking it makes file managers regenerate a preview instead of preserving the contradiction.

The turn is computed on this device; the file never leaves this tab.

Repair a JPEG orientation without recompressing

Read the EXIF instruction first, then rewrite only that field when the compressed picture data is already upright.

Drop a photo, or paste one.A JPEG from a phone or a scanner is the useful case: those are the files that carry a tag.

Nothing to hand?

The tag is read before any control appears, and the reading is shown in words rather than as a number between one and eight.

Lossless describes one operation, not the whole page

A JPEG orientation tag is an instruction attached to compressed picture data. If the pixels are already upright and the instruction is wrong, changing that field to 1 repairs the display without decoding the JPEG stream. The compressed scan is copied, so coefficients, chroma sampling and quantisation remain untouched.

If the pixels themselves are stored sideways and the destination ignores orientation, the tag cannot make that system comply. Baking the transform is then the compatible repair, but it creates a new JPEG. The tool keeps these choices separate and says which part of the file each one changes.

Checks before choosing

Compare how the file appears here with the program or portal where it failed.
Read the reported orientation value and its mirrored or rotated meaning rather than relying on the filename.
Keep the original until the repaired copy has been checked in both a tag-aware viewer and the destination that previously disagreed.

Questions about a lossless repair

Is every rotation on this page lossless?: No. Only rewriting the orientation field is byte-preserving for the compressed image data. Baking a turn into the pixels decodes and re-encodes the JPEG and is therefore a new lossy generation.
When is tag rewrite the correct repair?: When the stored pixels are already upright but the orientation field tells compliant viewers to turn or mirror them. The inspector describes the field before offering either repair.
Why is the embedded thumbnail unlinked?: A stale EXIF thumbnail can keep showing the old direction after the full image is repaired. Unlinking it makes file managers regenerate a preview instead of preserving the contradiction.