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NEW FORUM UPLOAD FEATURES
RoGeorge:
--- Quote from: Zero999 on July 01, 2019, 06:17:04 pm ---use Gimp to reduce the image to indexed, with a maximum palette of 256 colours
--- End quote ---
I tried indexed 256 colors palette for photos in JPG format, and to my surprise the result was 1-2KB larger than when the palette was left unchanged.
BravoV:
Imo, all problems with big sized photos/pictures still depend on the poster's knowledge and care.
Some are totally noob to be aware of that certain photo/picture is only suitable in lossy compression format like JPEG, while some are very good in lossless format like PNG. Google if any you still don't have any idea which is which is the most optimal for each type of photo/picture/illustration.
Of course, some are just ignorance, plain lazy and don't care shit about this. ::)
Also regarding photo shot from camera (not illustration like schematic), an excuse that only big sized file say like > 1MB is needed to bring the details, personally, I think that is excessive for most of the cases. An example from one of my photo posted here in this forum below, its only 120KB and I believe it has enough details presented to viewers to get my point.
Its about my rotting connector plastic that oozed out nasty flakes that I posted at other thread. :(
Click to enlarge
Of course, I did post huge file sized photos too, but that was intentional, as it needs all the details as much as possible for viewer to view the traces at 4 layers board with a backlighting. It was photos of PCB shots that I managed to custom adjust the compression level of two JPG files, at original camera's resolution with 1 MB each up to the forum's limit at that time which was 2 MB max in a single post. Example -> HERE
Zero999:
--- Quote from: RoGeorge on July 02, 2019, 05:27:33 am ---
--- Quote from: Zero999 on July 01, 2019, 06:17:04 pm ---use Gimp to reduce the image to indexed, with a maximum palette of 256 colours
--- End quote ---
I tried indexed 256 colors palette for photos in JPG format, and to my surprise the result was 1-2KB larger than when the palette was left unchanged.
--- End quote ---
What sort of image was it? A photograph by any chance? My comment regarding PNG and indexed colour, only applies to schematics and drawings, with large areas of either the same colour, or a repeating pattern. As mentioned above, PNG is no good for photographs. Use JPEG, smooth the image and use a lower quality setting to save space.
T3sl4co1l:
I voted < 500kB because that's a pretty safe maximum. There are very few cases where you should ever need more size than that in a single image. Average probably around 100k.
If you can't say it in 800x600 or such*, should you really be saying it at all? Consider first of all, cropping, brightening and sharpening your image. Second, if you must show detail, why not crop sections, or take macro shots? There is so much more information you can present, in so much better ways.
*This was once a common screen resolution, but that's largely of historical significance anymore, even among mobile devices (which have vertical or mixed aspect ratios, oddball numbers, and, some of them have bizarre cutouts in the display?...well, anyway... :-DD ). Anyway, similar number of pixels, about a half a megapixel, really.
Most people, simply give it no thought whatsoever, have no clue that this is even a thing to argue about -- they have no need or care of the details, they just want to get an image from here to there.
For their benefit, there could perhaps be an added step like, "Would you like your image to be reduced automatically?" The default option would be "yes", encouraging its use. Answering "no" might give a second nag, "would you like your image compressed for faster loading?", which would save it at JPG compression 80-90 say, or PNG indexed, whichever is smaller; assuming this isn't a tremendous load on the server of course**; and if declined both times, just let it through absolutely normal. Possibly add an option "Use these options for all attachments?" for when a user is posting a lot of images and doesn't want the nag every time. Or put it in the user profile as another option ("attachments: advanced mode" say?).
**It could be done clientside with a JS library, though I'm not sure quite how slow that would go. Which... oh neat, Canvas.toDataURL takes a type ("image/png" (default) or "image/jpeg" for example), with a second parameter for quality. So it's probably in most browsers to begin with, no page overhead, and it should be very fast.
But, speaking of laziness, it may well be more effort to introduce such a feature to the forum software, than it is to provide for the server and connections, and if most users aren't complaining about load times or poorly formatted images who cares, right?
Tim
Berni:
I wouldn't mind seeing an optional automatic image compression feature. But i think id only offer the feature for compressing down ridiculously large JPEG photos.
You don't want to convert a schematic in JPG format into a PNG. The PNG will try to encode all of the JPEG artifacts and grow the file size a lot. You can also have transparency in formats like PNG and GIF where automatic conversions sometimes fall on its face.
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