ImageMagick: No decode delegate for this image format `' @ error/constitute.c/ReadImage/504

brew remove imagemagick //to delete current versionbrew install imagemagick --build-from-source

fixed it for me on mac

Throwing in my two cents as I too have struggled with this problem for the last few days. I had no problem running ImageMagick commands on my local machine, but got the error message as mentioned by OP when I ran the command from a Tomcat server running on Azure Cloud.

I could identify the cause by running the following command:

convert -list format

On my local machine, it would return quite a long list of all the supported formats, whereas on Kudu (Azure CLI tool) it would return an empty result. This indicates ImageMagick didn't find the path to its DLL files required for processing.

In my case, the problem was simply caused by a lack of configuration on Azure:

• The absence of the ImageMagick root folder in the system environment variable %PATH%
• The absence of an environment variable "MAGICK_HOME" (set to the root folder of your ImageMagick installation directory)
• The absence of an environment variable "MAGICK_CODER_MODULE_PATH" (set to the folder mentioned above + /modules/coders)

NOTE: for people who are also experiencing this problem on Azure, you can have a look at this SO answer which explains how to add an environment variable using an XDT Transform.

I had the same error on Ubuntu 20.04 and ImageMagick.Had to reinstalled ImageMagick with all add ons according to this instruction:

#These are the steps required in order to Install ImageMagick with JPG, PNG and TIFF delegates.sudo apt-get update #Install Build-Essential in order to configure and make the final Installsudo apt-get install build-essential #libjpg62-dev required in order to work with basic JPG filessudo apt-get install -y libjpeg62-dev #libtiff-dev is required in order to work with TIFF file formatsudo apt-get install -y libtiff-dev #Download ImageMagickwget https://www.imagemagick.org/download/ImageMagick.tar.gz #Untar Imagemagicktar xvzf ImageMagick.tar.gz #Access the working directorycd ImageMagick/[version_number] #Configure and make sure to disable the "shared" option./configure --disable-shared#Makesudo make#Installsudo make install#Final Checksudo make check