Secret to making an avatar <= 6kb???

[some_evil]

Is there a secret to making a jpg smaller so as we can use as an avatar? If I keep resizing my jpg it becomes unrecognisable at 30kb, yet i see some pretty cool avatars here so it must be possible.


Are there any secrets to doing this?

Cheers

[DougieLawson]

Convert it to GIF then convert it back to JPG. GIF reduces the colour map to 256 but doesn't lose too much detail.

[some_evil]

Dougie you seem to be my saviour of late, thanks again.

Although when I saved the GIF back to JPG its filesize grew back to original size, but the GIF was down at 5kb, so i ended up using that one.

Thanks again.

[mahjongg]

it seems to have worked.

[expandables]

My avatar was this http://postimg.org/image/6echqme9b/

[mahjongg]

yeah, for some reason some media liked to publish "non-flattering" pictures of him....

[Mandrewpi]

How do you upload images for your avatar? I went to the avatar page browsed for an avatar pic on my phone (within all requirements) but I tried to save it and it doesn't show up

[some_evil]

How do you upload images for your avatar? I went to the avatar page browsed for an avatar pic on my phone (within all requirements) but I tried to save it and it doesn't show up

Haven't changed avatar using my phone, have you tried on a PC? Go to user Control Panel, Profile then Edit Avatar...

[Mandrewpi]

Yea that didn't work either, I will just go without one for now

[some_evil]

Yea that didn't work either, I will just go without one for now

Can you screenshot what you can/cannot see on your control panel for us to see?

[AndyD]

Convert it to GIF then convert it back to JPG. GIF reduces the colour map to 256 but doesn't lose too much detail.

How are you making your avatars? I think you would get a better looking avatar by decreasing the "quality" (when saving your JPEG) in the image manipulation program you are using, until you reach the desired size. A small amount of Gaussian blur will often reduce the size of the file.

When you quantize a 24 bit-per-pixel image to a 256-colour palette, the image will often be dithered to randomize the resulting errors. This increases the noise in the image and may reduce the amount of (JPEG) compression.

The size of the uncompressed avatar is 90 x 90 x 3 =24,300 bytes, and needs to be compressed to 6 KiB (6,144 bytes). So needs to be compressed to around 25% of the original (including headers etc).

When using JPEG compression, the size of the resulting file depends on a number of things:

• The amount of metadata in the APP* segments (exif, thumbnails, etc)
• The amount of "information" in the original image
• The "quality" (amount of quantization of the discrete cosine transform coefficients)
• The amount of chroma sub-sampling (4:4:4. 4:2:2 or 4:2:0, these often kick in a specific quality values)
• Baseline vs "optimized" Huffman encoding

"Quality" and chroma sub-sampling can often be selected when you save the file.
You can use jpegtran (found in the libjpeg-progs package) to remove metadata and create optimized Huffman tables, without recalculating the DCT or re-quantizing.