diff --git a/README.md b/README.md
index 9dcc178..f7c8223 100644
--- a/README.md
+++ b/README.md
@@ -270,19 +270,23 @@ BTCPAY_SSHKEYFILE=/datadir/id_rsa
 1. Add support for your crypto to [NBitcoin](https://github.com/MetacoSA/NBitcoin/tree/master/NBitcoin.Altcoins), [NBxplorer](https://github.com/dgarage/NBXplorer), and [BTCPayServer](https://github.com/btcpayserver/btcpayserver). (Use examples from other coins)
 2. Create your own docker image ([Example for BTC](https://hub.docker.com/r/nicolasdorier/docker-bitcoin/))
 3. Create a docker-compose fragment ([Example for BTC](docker-compose-generator/docker-fragments/bitcoin.yml))
-4. Add your CryptoDefinition ([Example for BTC](docker-compose-generator/src/CryptoDefinition.cs))
+4. Add your `CryptoDefinition` ([Example for BTC](docker-compose-generator/src/CryptoDefinition.cs))
 
-When testing your coin, **DO NOT USE `build.sh`**, since it uses a pre-built docker image.
-
-Instead, install [.NET Core 2.1 SDK](https://www.microsoft.com/net/download/windows) and run:
+`build.sh` is using a pre-built image of the `docker-compose generator` on [docker hub](https://hub.docker.com/r/btcpayserver/docker-compose-generator/).
+If you modify the code source of `docker-compose generator` (for example, the `CryptoDefinition` [Example for BTC](docker-compose-generator/src/CryptoDefinition.cs)), you need to configure `build.sh` to use your own image by setting the environment variable `BTCPAYGEN_DOCKER_IMAGE` to `btcpayserver/docker-compose-generator:local`.
 
 ```bash
-BTCPAYGEN_CRYPTO1="EXAMPLE-COIN"
-BTCPAYGEN_SUBNAME="test"
-cd docker-compose-generator/src
-dotnet run
+cd docker-compose-generator
+BTCPAYGEN_DOCKER_IMAGE="btcpayserver/docker-compose-generator:local"
+```
+
+Or on powershell:
+```powershell
+cd docker-compose-generator
+$BTCPAYGEN_DOCKER_IMAGE="btcpayserver/docker-compose-generator:local"
 ```
 
+Then run `./build.sh` or `. .\build.ps1`.
 This will generate your docker-compose in the `Generated` folder, which you can then run and test.
 
 Note that BTCPayServer developers will not spend excessive time testing your image, so make sure it works.
diff --git a/build.ps1 b/build.ps1
index 840d9a4..ec7f8fb 100755
--- a/build.ps1
+++ b/build.ps1
@@ -1,6 +1,13 @@
 # This script will run docker-compose-generator in a container to generate the yml files
 
-docker pull btcpayserver/docker-compose-generator
+If (-not ($BTCPAYGEN_DOCKER_IMAGE)) { $BTCPAYGEN_DOCKER_IMAGE = "btcpayserver/docker-compose-generator" }
+
+If ($BTCPAYGEN_DOCKER_IMAGE -eq "btcpayserver/docker-compose-generator:local"){
+	docker build docker-compose-generator --tag $BTCPAYGEN_DOCKER_IMAGE
+} Else {
+	docker pull $BTCPAYGEN_DOCKER_IMAGE
+}
+
 docker run -v "$(Get-Location)\Generated:/app/Generated" `
            -v "$(Get-Location)\docker-compose-generator\docker-fragments:/app/docker-fragments" `
            -e "BTCPAYGEN_CRYPTO1=$BTCPAYGEN_CRYPTO1" `
@@ -16,7 +23,7 @@ docker run -v "$(Get-Location)\Generated:/app/Generated" `
            -e "BTCPAYGEN_ADDITIONAL_FRAGMENTS=$BTCPAYGEN_ADDITIONAL_FRAGMENTS" `
            -e "BTCPAYGEN_LIGHTNING=$BTCPAYGEN_LIGHTNING" `
            -e "BTCPAYGEN_SUBNAME=$BTCPAYGEN_SUBNAME" `
-           --rm btcpayserver/docker-compose-generator
+           --rm $BTCPAYGEN_DOCKER_IMAGE
 
 If ($BTCPAYGEN_REVERSEPROXY -eq "nginx") {
     Copy-Item ".\Production\nginx.tmpl" -Destination ".\Generated"
diff --git a/build.sh b/build.sh
index 62b1a65..b3fab27 100755
--- a/build.sh
+++ b/build.sh
@@ -1,7 +1,14 @@
 #!/bin/bash
 
+: "${BTCPAYGEN_DOCKER_IMAGE:=btcpayserver/docker-compose-generator}"
+if [ "$BTCPAYGEN_DOCKER_IMAGE" == "btcpayserver/docker-compose-generator:local" ]
+then
+    docker build docker-compose-generator --tag $BTCPAYGEN_DOCKER_IMAGE
+else
+    docker pull $BTCPAYGEN_DOCKER_IMAGE
+fi
+
 # This script will run docker-compose-generator in a container to generate the yml files
-docker pull btcpayserver/docker-compose-generator
 docker run -v "$(pwd)/Generated:/app/Generated" \
            -v "$(pwd)/docker-compose-generator/docker-fragments:/app/docker-fragments" \
            -e "BTCPAYGEN_CRYPTO1=$BTCPAYGEN_CRYPTO1" \
@@ -17,7 +24,7 @@ docker run -v "$(pwd)/Generated:/app/Generated" \
            -e "BTCPAYGEN_ADDITIONAL_FRAGMENTS=$BTCPAYGEN_ADDITIONAL_FRAGMENTS" \
            -e "BTCPAYGEN_LIGHTNING=$BTCPAYGEN_LIGHTNING" \
            -e "BTCPAYGEN_SUBNAME=$BTCPAYGEN_SUBNAME" \
-           --rm btcpayserver/docker-compose-generator
+           --rm $BTCPAYGEN_DOCKER_IMAGE
 
 if [ "$BTCPAYGEN_REVERSEPROXY" == "nginx" ]; then
     cp Production/nginx.tmpl Generated/nginx.tmpl