Once a file was picked the preview <img> overlaid the file input and
blocked further clicks, so the drop zone became read-only. Making the
preview and the new 'Click to change' hint pointer-events:none lets
clicks pass through to the input again.
Also parses the JPEG APP1 EXIF segment inline (no dependency) to read
DateTimeOriginal and prefill the date field. Falls back to the file's
lastModified for PNGs or JPEGs without EXIF. The date field stays
editable in either case.
puttaalu
b26bef0296