diff --git a/docker-compose.yml b/docker-compose.yml
index fd242ea..25e34f2 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -8,7 +8,6 @@ services:
             RAM_SIZE: "1G"
             CPU_CORES: "1"
             DISK_SIZE: "16G"
-            DISK_FMT: "qcow2"
             BOOT: "https://dl-cdn.alpinelinux.org/alpine/v3.18/releases/x86_64/alpine-standard-3.18.2-x86_64.iso"
         devices:
             - /dev/kvm
diff --git a/readme.md b/readme.md
index 007a31d..9df6ee5 100644
--- a/readme.md
+++ b/readme.md
@@ -32,8 +32,6 @@ services:
     image: qemux/qemu-docker:latest
     environment:
       DISPLAY: "vnc"
-      DISK_SIZE: "16G"
-      DISK_FMT: "qcow2"
       BOOT: "https://dl-cdn.alpinelinux.org/alpine/v3.18/releases/x86_64/alpine-standard-3.18.2-x86_64.iso"
     devices:
       - /dev/kvm
@@ -48,7 +46,7 @@ services:
 Via `docker run`
 
 ```bash
-docker run -it --rm -e "BOOT=http://www.example.com/image.iso" --device=/dev/kvm --cap-add NET_ADMIN qemux/qemu-docker:latest
+docker run -it --rm -e "BOOT=http://www.example.com/image.iso" -p 5900:5900 --device=/dev/kvm --cap-add NET_ADMIN qemux/qemu-docker:latest
 ```
 
 ## FAQ
@@ -66,7 +64,7 @@ docker run -it --rm -e "BOOT=http://www.example.com/image.iso" --device=/dev/kvm
 
   * ### How do I change the size of the data disk?
 
-    To expand the default size of 16 GB, locate the `DISK_SIZE` setting in your compose file and modify it to your preferred capacity:
+    To expand the default size of 16 GB, add the `DISK_SIZE` setting to your compose file and set it to your preferred capacity:
 
     ```yaml
     environment:
@@ -86,17 +84,6 @@ docker run -it --rm -e "BOOT=http://www.example.com/image.iso" --device=/dev/kvm
 
     Replace the example path `/home/user/data` with the desired storage folder.
 
-  * ### How do I create a growable disk?
-
-    By default, the entire capacity of the disk is reserved in advance. To create a growable disk that only allocates space that is actually used, add the following environment variable:
-
-    ```yaml
-    environment:
-      DISK_FMT: "qcow2"
-    ```
-
-    This can also be used to convert any existing disks to the ```qcow2``` format.
-
   * ### How do I increase the amount of CPU or RAM?
 
     By default, a single core and 1 GB of RAM are allocated to the container. To increase this, add the following environment variables:
@@ -184,6 +171,17 @@ docker run -it --rm -e "BOOT=http://www.example.com/image.iso" --device=/dev/kvm
 
     Afterwards you can connect with any VNC client to port 5900.
 
+  * ### How do I passthrough the GPU?
+
+    To passthrough your Intel GPU, add the following lines to your compose file:
+
+    ```yaml
+    environment:
+      GPU: "Y"
+    devices:
+      - /dev/dri
+    ```
+
   * ### How do I provide custom arguments to QEMU?
 
     You can create the `ARGUMENTS` environment variable to provide additional arguments to QEMU at runtime:
diff --git a/src/disk.sh b/src/disk.sh
index ba31365..a239a73 100644
--- a/src/disk.sh
+++ b/src/disk.sh
@@ -4,7 +4,7 @@ set -Eeuo pipefail
 # Docker environment variables
 
 : ${DISK_IO:='native'}    # I/O Mode, can be set to 'native', 'threads' or 'io_turing'
-: ${DISK_FMT:='raw'}      # Disk file format, "raw" by default for backwards compatibility
+: ${DISK_FMT:=''}      # Disk file format, can be set to "raw" or "qcow2" (default)
 : ${DISK_CACHE:='none'}   # Caching mode, can be set to 'writeback' for better performance
 : ${DISK_DISCARD:='on'}   # Controls whether unmap (TRIM) commands are passed to the host.
 : ${DISK_ROTATION:='1'}   # Rotation rate, set to 1 for SSD storage and increase for HDD
@@ -261,6 +261,14 @@ addDisk () {
   return 0
 }
 
+if [ -z "$DISK_FMT" ]; then
+  if [ -f "$STORAGE/data.img" ]; then
+    DISK_FMT="raw"
+  else
+    DISK_FMT="qcow2"
+  fi
+fi
+
 DISK_EXT="$(fmt2ext "$DISK_FMT")" || exit $?
 
 DISK1_FILE="$STORAGE/data"