image-formatsjpegrgb
All my photo's are JPEG images (e.g. IMG_1202.JPG), which say sRGB under colour representation.
I want to upload photo's to iSTOCK, and they require RGB JPG files only. TIFs, PNGs and PSDs will be declined. CMYK images will also be declined.
Are my photo's fine as they are, or do I have to convert them in any way before I upload them to iSTOCK ?
Thanks.
Your DSC02322-bad.jpg file is 2178036 nul bytes (i.e. 2178036 single byte zeros):
$ hexdump DSC02322-bad.jpg
0000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
0213bf0
Your DSC02322-good.jpg file is 2178036 bytes of JPEG data. There's nothing to repair in DSC02322-bad.jpg as there's nothing left.
By the way, the file command says "data" when it doesn't know what else to say.
Edit: Fixed some issues with the original script. Added an alternative one based on Marcks Thomas' proposition.
Edit 2: Updated cutoff values based on a number of test runs. I am still not sure how to estimate file sizes for greyscale images. If you are working with a large number of images outside of RGB colour schemes you might want to implement the first script as a fallback mode to the second one.
Edit 3: Added optipng integration. This optimizes PNG file sizes without any quality loss. See here for more information. Some smaller improvements.
Version 0.1
Important note: This script is deprecated. Newer versions are far more efficient.
Alright, my question might have been slightly too localized, so I put some time into it and compiled the script myself:
#!/bin/bash
# AUTHOR: (c) MHC (http://askubuntu.com/users/81372/mhc)
# NAME: Intelliconvert 0.1
# DESCRIPTION: A script to automate and optimize the choice between different image formats.
# LICENSE: GNU GPL v3 (http://www.gnu.org/licenses/gpl.html)
# REQUIREMENTS: Imagemagick
ORIGINAL="$1"
###Filetype check###
MIME=$(file -ib "$ORIGINAL")
if [ "$MIME" = "image/png; charset=binary" ]
then
echo "PNG Mode"
###Variables###
##Original Image##
FILENAME=$(basename "$ORIGINAL")
PARENTDIR=$(dirname "$ORIGINAL")
SUBFOLDER=$(echo "$PARENTDIR" | cut -d"/" -f10-)
ORIGARCHIVE="~/ORIG"
##Converted Image##
TEMPDIR="/tmp/imgcomp"
CONVERTED="$TEMPDIR/$FILENAME.jpg"
##Image comparison##
DIFFLO="50"
DIFFHI="75"
CUTOFF="1000000"
##DEBUG
echo "#### SETTINGS ####"
echo "Filepath to original = $ORIGINAL"
echo "Filename= $FILENAME"
echo "Parent directory = $PARENTDIR"
echo "Archive directory = $ORIGARCHIVE"
echo "Temporary directory = $TEMPDIR"
echo "Filepath to converted image = $CONVERTED"
echo "Low cut-off = $DIFFLO"
echo "High cut-off = $DIFFHI"
###Conversion###
convert -quality 92 -flatten -background white "$ORIGINAL" "$CONVERTED"
###Comparison###
F1=$(stat -c%s "$ORIGINAL" )
F2=$(stat -c%s "$CONVERTED" )
FQ=$(echo "($F2*100/$F1)" | bc)
#Depending on filesize we use a different Cut-off#
if [ "$F1" -ge "$CUTOFF" ]
then
DIFF="$DIFFHI"
else
DIFF="$DIFFLO"
fi
##DEBUG
echo "### COMPARISON ###"
echo "Filesize original = $F1 Bytes"
echo "Filesize converted = $F2 Bytes"
echo "Chosen cut-off = $DIFF %"
echo "Actual Ratio = $FQ %"
if [ "$FQ" -le "$DIFF" ]
then
echo "JPEG is more efficient, converting..."
mv -v "$CONVERTED" "$PARENTDIR"
mkdir -p "$ORIGARCHIVE/$SUBFOLDER"
mv -v "$ORIGINAL" "$ORIGARCHIVE/$SUBFOLDER"
else
echo "PNG is fine, exiting."
rm -v "$CONVERTED"
fi
else
echo "File does not exist or unknown MIME type, exiting."
fi
The script works great in combination with Watcher.
This is my first proper script, so there might be some unresolved bugs and issues I just didn't see. Feel free to use it for yourself and improve it. If you do so, I'd appreciate it if you could leave a comment here, so that I can learn from it.
Version 0.2.1
A more efficient way of finding the right format can be achieved by comparing the original's file size to its estimated size as an uncompressed image:
#!/bin/bash
# AUTHOR: (c) MHC (http://askubuntu.com/users/81372/mhc)
# NAME: Intelliconvert 0.2.1
# DESCRIPTION: A script to automate and optimize the choice between different image formats.
# LICENSE: GNU GPL v3 (http://www.gnu.org/licenses/gpl.html)
# REQUIREMENTS: Imagemagick, Optipng
################ Filetype Check#################
MIME=$(file -ib "$1")
if [ "$MIME" = "image/png; charset=binary" ]
then
echo "###PNG Mode###"
####################Settings####################
##Folders##
ORIGARCHIVE="~/ORIG"
##Comparison##
DIFFLO="25"
DIFFHI="20"
CUTOFF="1000000"
################################################
###Variables###
ORIGINAL="$1"
FILENAME=$(basename "$ORIGINAL")
PARENTDIR=$(dirname "$ORIGINAL")
SUBFOLDER=$(echo "$PARENTDIR" | cut -d"/" -f10-)
CONVERTED="$PARENTDIR/$FILENAME.jpg"
#DEBUG#
echo "###SETTINGS###"
echo "Filepath to original = $ORIGINAL"
echo "Filename= $FILENAME"
echo "Parent directory = $PARENTDIR"
echo "Archive directory = $ORIGARCHIVE"
echo "Filepath to converted image = $CONVERTED"
echo "Low cut-off = $DIFFLO"
echo "High cut-off = $DIFFHI"
###Image data###
WIDTH=$(identify -format "%w" "$ORIGINAL")
HEIGHT=$(identify -format "%h" "$ORIGINAL")
ZBIT=$(identify -format "%z" "$ORIGINAL")
COL=$(identify -format "%[colorspace]" "$ORIGINAL")
F1=$(stat -c%s "$ORIGINAL")
if [ "$COL" = "RGB" ]
then
CHANN="3"
else
CHANN="1"
fi
###Cutoff setting###
if [ "$F1" -ge "$CUTOFF" ]
then
DIFF="$DIFFHI"
else
DIFF="$DIFFLO"
fi
###Calculations on uncompressed image###
BMPSIZE=$(echo "($WIDTH*$HEIGHT*$ZBIT*$CHANN/8)" | bc)
FR=$(echo "($F1*100/$BMPSIZE)" | bc)
#DEBUG#
echo "###IMAGE DATA###"
echo "Image Dimensions = $WIDTH x $HEIGHT"
echo "Colour Depth = $ZBIT"
echo "Colour Profile = $COL"
echo "Channels = $CHANN"
echo "Estimated uncompressed size = $BMPSIZE"
echo "Actual file size = $F1"
echo "Estimated size ratio = $FR %"
echo "Cutoff at $DIFF %"
###Backup###
echo "###BACKUP###"
mkdir -p "$ORIGARCHIVE/$SUBFOLDER" #keep the original folder structure
cp -v "$ORIGINAL" "$ORIGARCHIVE/$SUBFOLDER"
echo ""
###Comparison###
if [ "$FR" -ge "$DIFF" ]
then
echo "JPEG is more efficient, converting..."
convert -quality 92 -flatten -background white "$ORIGINAL" "$CONVERTED"
echo "Done."
echo "Cleaning up..."
rm -v "$ORIGINAL"
else
echo "PNG is fine, passing over to optipng."
echo "Optimizing..."
optipng "$ORIGINAL"
echo "Done."
fi
################ Filetype Check#################
else
echo "File does not exist or unknown MIME type, exiting."
fi
Props to @Marcks Thomas for the great idea.
Best Answer
I assume they mean an image file with an RGB color profile, such as the sRGB profile in your photo. An actual RGB encoded JPEG file is not very common. You should be able to submit the photos as is.
JPEG files are usually encoded from an RGB source image into a YCbCr intermediate before they are compressed, then when decoded are rendered back to RGB. YCbCr allows the brightness component of the image to be compressed at a different rate than the color components, which allows for a better compression ratio.
An RGB native JPEG compresses the RGB source directly without an intermediate format, which results in a larger file size for the required quality setting, so native format compression would only used in cases where the quality is set to maximum, and even then few compressors actually do this.
The color profile allows the decoder to display the image with the same colors as the source data, which in your case is sRGB, generally used with standard 24-bit color on computer monitors, digital cameras, web cams, and home printers. AdobeRGB is also used, usually with professional images, which renders a more true green on devices that can support it. JPEG can also compress grayscale and CMYK. CMYK images are usually converted to YCbCrK intermediate before compression, but like RGB can be compressed without conversion.
The color profile is not actually part of the JPEG compression standard, but part of the interchange formats (JIF, JFIF, EXIF) that specify how .jpg files are formatted, and how they are displayed. A file without a color profile is assumed to be rendered as sRGB after it is decompressed and decoded.