RAW photos previews using exiftool

[giovariot]

Is your feature request related to a problem? Please describe.
I've noticed RAW files are currently unsupported by the website, they are correctly shown as pictures files with a generic picture icon. I think adding support for thumbnailing and preview could be quite easy to implement.

Describe the solution you'd like
Most of the raw files I know how actually already contain a jpeg formatted thumbnail and preview file.
You can output them with the following exiftool commands:

• Thumbnail: exiftool -b -ThumbnailImage sample1.cr2 > thumbnail.jpg
• Preview: exiftool -b -PreviewImage sample1.cr2 > preview.jpg

Here is a table generated with gemini of all the raw formats containing previews

Manufacturer	File Extension(s)	Embedded Thumbnail	Large Preview	Notes
Canon	.CR2, .CR3, .CRW	Yes	Yes	.CR3 (newer) can embed very high-quality previews.
Nikon	.NEF, .NRW	Yes	Yes	Typically embeds a full-resolution JPEG.
Sony	.ARW, .SRF, .SR2	Yes	Variable	Older models often used reduced-res previews.
Fujifilm	.RAF	Yes	Variable	Often embeds a medium-res preview rather than full.
Adobe	.DNG	Yes	Yes	Fully customizable; newer "lossy" DNGs use JPEG XL.
Olympus / OM	.ORF, .ORI	Yes	Yes	.ORI is often a secondary file for specific modes.
Panasonic	.RW2, .RAW, .RWL	Yes	Yes	.RWL is shared with Leica systems.
Pentax	.PEF, .PTX	Yes	Yes	High compatibility with DNG (can often switch in-camera).
Leica	.DNG, .RWL	Yes	Yes	Most modern Leicas use standard DNG.
Hasselblad	.3FR, .FFF	Yes	Yes	.FFF is the "native" format for digital backs.
Phase One	.IIQ	Yes	Yes	"Intelligent Image Quality"—embeds high-res previews.
Mamiya	.MEF	Yes	Yes	Legacy medium format; usually standard TIFF-based.
Leaf	.MOS	Yes	Yes	Used by Leaf Aptus/Valeo digital backs.
Sigma	.X3F	Yes	Yes	Unique "Foveon" sensor data; usually has a full JPEG.
Kodak	.DCR, .KDC, .K25	Yes	Variable	Some legacy .K25 files only have tiny thumbnails.
Samsung	.SRW	Yes	Yes	Found in the now-discontinued NX series.
Epson	.ERF	Yes	Yes	Specifically for the R-D1 rangefinder series.
Casio	.BAY	Yes	Yes	Used in older Exilim high-speed cameras.
Blackmagic	.BRAW	Yes	Yes	Designed for video; uses a sidecar/embedded hybrid.
RED Cinema	.R3D	Yes	Yes	Usually requires specific SDKs to view the preview.
GoPro	.GPR	Yes	Yes	A "General Purpose RAW" based on the DNG spec.
Ricoh	.DNG	Yes	Yes	Ricoh was an early adopter of the universal DNG standard.
Minolta	.MRW	Yes	Yes	Legacy format for DiMAGE series; usually high-res preview.
Sinar	.CS1, .STI	Yes	Yes	High-end studio cameras; very structured metadata.
Logitech	.PXN	Yes	No	Extremely rare legacy format; mostly tiny thumbnails.

Describe alternatives you've considered
LibRaw too should enable the fast extraction of previews and thumbnails, with also support for some types of custom DNG files that are missing a proper preview. Here is another table I created with gemini to summarize the different methods

Stage	Target	Primary Method (Fastest)	Failsafe Method (Back-up)	LibRaw Efficiency Logic
Thumbnail	~160px icons	unpack_thumb()	Downsampled Linear Decode	If unpack_thumb() fails, run unpack() with params.half_size = 1 and further downscale the buffer.
Preview	1080p - 4K	unpack_thumb()*	Half-Size Demosaic	Use params.user_qual = 0 (Bilinear) and params.half_size = 1 for a "good enough" view at 4x speed.
Full View	Full Res	N/A	Standard Process	params.user_qual = 3 (AHD) or better. This is the "slow" lane; no shortcuts here.

*Note: Many modern cameras embed a full-size JPEG in the thumbnail slot

Additional context
This would allow to save lots of bandwidth server-side since most user could simply decide to download only a few files they're interested in instead of downloading whole folders.
I also think this extraction could easily be done client-side with exiftool and libraw libraries support and ports for multiple programming languages