Demo imageprovider docs (#4273)

Author: klucsik

content/en/docs/demo/_index.md

@@ -52,6 +52,7 @@ found here:
 - [Quote Service](services/quote/)
 - [Recommendation Service](services/recommendation/)
 - [Shipping Service](services/shipping/)
+- [Image Provider Service](services/imageprovider/)
 
 ## Scenarios
 

content/en/docs/demo/architecture.md

@@ -22,6 +22,7 @@ emailservice(Email Service):::ruby
 frauddetectionservice(Fraud Detection Service):::kotlin
 frontend(Frontend):::typescript
 frontendproxy(Frontend Proxy <br/>&#40Envoy&#41):::cpp
+imageprovider(Image Provider <br/>&#40nginx&#41):::cpp
 loadgenerator([Load Generator]):::python
 paymentservice(Payment Service):::javascript
 productcatalogservice(Product Catalog Service):::golang
@@ -33,6 +34,7 @@ queue[(queue<br/>&#40Kafka&#41)]
 Internet -->|HTTP| frontendproxy
 frontendproxy -->|HTTP| frontend
 loadgenerator -->|HTTP| frontendproxy
+frontendproxy -->|HTTP| imageprovider
 
 queue -->|TCP| accountingservice
 queue -->|TCP| frauddetectionservice

content/en/docs/demo/services/imageprovider.md

@@ -0,0 +1,10 @@
+---
+title: Image Provider Service
+linkTitle: Image Provider
+---
+
+This service provides the images which are used in the frontend. The images are
+statically hosted on a NGINX instance. The NGINX server is instrumented with the
+[nginx-otel module](https://github.com/nginxinc/nginx-otel/tree/main).
+
+[Image Provider service source](https://github.com/open-telemetry/opentelemetry-demo/blob/main/src/imageprovider/)