ImageMagick mogrify does not overwrite original files

formatimagemagick

I would like to convert image formats.

I can use 'convert' command, but it made another image.

So I searched and find 'mogrify' command in ImageMagick official page.

What I did was

mogrify -format png a.jpg

What I expected was one image that has 'png' extension.

But it did not overwrite original image, but made another png image in my folder.

How Can I get only one image(that means overwite original file) in some format

that I want?

Thanks:-)

Best Answer

ImageMagick's mogrify isn't the best tool here, turns out convert is much better suited for the job. It can be done by specifying output format with the file name.

convert a.jpg png:a.jpg

Example:

$ file a.jpg 
a.jpg: JPEG image data, JFIF standard 1.01
$ convert a.jpg png:a.jpg
$ file a.jpg 
a.jpg: PNG image data, 300 x 199, 8-bit/color RGB, non-interlaced

Related Solutions

Convert file to 24bit bitmap

I have had some trouble with BMP conversions too. I have typically specified BMP3:outfile.bmp and I normally get 24 bit BMP files. sometimes I get an 8 bit BMP when converting JPEG files. I just tried the -type truecolor (having seen it here) and now it looks like I get a 24 bit BMP in the cases where I used to get only 8 bits.

I also use these switches:

-units PixelsPerInch -density 72 -compress None -depth 24

the -depth 24 should do a 24 bit BMP (the depth -8 in your case may also be causing a problem) but as I said I sometimes get 8 bits even with the 24 specified.

the -units and -density cases corrected a problem where sometimes I would get a 0 for the biXPelsPerMeter and biYPelsPerMeter fields in the BMP header (it did not seem to cause a problem though). by the way I have not found a good explanation of these 2 fields.

the -compress None was required because sometimes a conversion generated a compressed BMP - no logical reason for doing that was found.

hopefully this will be of some help but I am not an expert on this subject - I just tried a few things and looked around using Google and came up with the above switch settings.

Trimming exterior empty space with ImageMagick does not work on scanned documents

You can use -shave and simply shave off the edges and then use the logic you use afterwards to process accordingly.

Note: The amount you shave off (e.g. the argument after "-shave" 40x40 or 10x10, etc. ) is important so be sure to test thoroughly to ensure this setting works universally in your environment for your images.

Example Logic

@ECHO ON

SET Convert="C:\Program Files\ImageMagick\Convert.exe"
%convert% C:\Folder\Circle.jpg -shave 40x40 C:\Folder\ShavedCircle.jpg
<The rest of your logic against C:\Folder\ShavedCircle.jpg now>

Before

After

Further Resources

Shave, removing edges from a image

The reverse of the "-border" or "-frame" operators, is "-shave", which if given the same arguments, will remove the space added by these commands.

The main thing to keep in mind about these three operators is that they add and remove space on opposite sides of the images, not just one side, or adjacent sides.

If you want to only remove one edge of an image, then you will need to use the "-chop" operator instead. (See the Chop Examples below).

As before all the operators "-border", "-frame", and "-shave", only effect the real image on the virtual canvas and not the virtual canvas itself.

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