Update pressure.sh

shell/pressure.sh

@@ -1,5 +1,13 @@
 #!/bin/bash
 
+# Check if ImageMagick is installed
+if ! command -v convert &> /dev/null; then
+    echo "Need ImageMagick as a dependency. Install it with:"
+    echo "  sudo apt-get install imagemagick   # For GNU/Linux"
+    echo "  brew install imagemagick           # For macOS"
+    exit 1
+fi
+
 # Check if both directory and quality are provided
 if [ -z "$1" ] || [ -z "$2" ]; then
     echo "Usage: $0 <directory> <quality>"