I have a Canon SX60, able to generate HDR pics.
I would like to know how can I detect a HDR image just checking the EXIF data, and if I can know about the different exposure details.
Your posted image, when inspected with ExifTool, shows
Easy Mode : High Dynamic Range Shooting Mode : High Dynamic Range
The exposure details are only for one of the exposures, of course.
At least in some camera models it looks like Canon store the following in EXIF:
HDR Shooting: Enable/Disable
Adjust dynamic range: Enable/Disable
HDR Effect: Natural/Art Standard/etc.
Auto Image Align: Enable/Disable
What you see may depend on the tool you use. The Canon software would most likely display it. Not sure if Exiftool would.
One of the latter comments on a Lightroom Metadata plugin (link) mentions the above fields being shown by the Canon software for a 600D.
If you've done a single shot HDR image (in-camera) I suspect you won't see the range of values used in the shutter speed/aperture/ISO fields - probably just one value.