diff --git a/conf/defaults.ini b/conf/defaults.ini
index 173f4babdf5..bb66626204b 100644
--- a/conf/defaults.ini
+++ b/conf/defaults.ini
@@ -1562,6 +1562,10 @@ rendering_verbose_logging =
 # Default is false. This can be useful to enable (true) when troubleshooting.
 rendering_dumpio =
 
+# Instruct headless browser instance whether to register metrics for the duration of every rendering step. Default is false.
+# This can be useful to enable (true) when optimizing the rendering mode settings to improve the plugin performance or when troubleshooting.
+rendering_timing_metrics =
+
 # Additional arguments to pass to the headless browser instance. Default is --no-sandbox. The list of Chromium flags can be found
 # here (https://peter.sh/experiments/chromium-command-line-switches/). Multiple arguments is separated with comma-character.
 rendering_args =
diff --git a/docs/sources/setup-grafana/configure-grafana/_index.md b/docs/sources/setup-grafana/configure-grafana/_index.md
index 1cc623b843e..9e6a30d948e 100644
--- a/docs/sources/setup-grafana/configure-grafana/_index.md
+++ b/docs/sources/setup-grafana/configure-grafana/_index.md
@@ -2302,6 +2302,14 @@ Instruct headless browser instance whether to output its debug and error message
 
 It can be useful to set this to `true` when troubleshooting.
 
+### rendering_timing_metrics
+
+> **Note:** Available from grafana-image-renderer v3.9.0+
+
+Instruct a headless browser instance on whether to record metrics for the duration of every rendering step. Default is `false`.
+
+Setting this to `true` when optimizing the rendering mode settings to improve the plugin performance or when troubleshooting can be useful.
+
 ### rendering_args
 
 Additional arguments to pass to the headless browser instance. Defaults are `--no-sandbox,--disable-gpu`. The list of Chromium flags can be found at (https://peter.sh/experiments/chromium-command-line-switches/). Separate multiple arguments with commas.
diff --git a/docs/sources/setup-grafana/image-rendering/_index.md b/docs/sources/setup-grafana/image-rendering/_index.md
index 8639cb7f7d0..61fd88e13dc 100644
--- a/docs/sources/setup-grafana/image-rendering/_index.md
+++ b/docs/sources/setup-grafana/image-rendering/_index.md
@@ -229,6 +229,25 @@ ENABLE_METRICS=true
 }
 ```
 
+#### Enable detailed timing metrics
+
+With the [Prometheus metrics enabled](#enable-prometheus-metrics), you can also enable detailed metrics to get the duration of every rendering step.
+
+Default is `false`.
+
+```bash
+# Available from v3.9.0+
+RENDERING_TIMING_METRICS=true
+```
+
+```json
+{
+  "rendering": {
+    "timingMetrics": true
+  }
+}
+```
+
 #### Log level
 
 Change the log level. Default is `info` and will include log messages with level `error`, `warning` and `info`.
@@ -370,6 +389,11 @@ BROWSER_TZ=Europe/Stockholm
 Instruct headless browser instance to use a default language when not provided by Grafana, e.g. when rendering panel image of alert.
 Refer to the HTTP header Accept-Language to understand how to format this value.
 
+```bash
+# Available from v3.9.0+
+RENDERING_LANGUAGE="fr-CH, fr;q=0.9, en;q=0.8, de;q=0.7, *;q=0.5"
+```
+
 ```json
 {
   "rendering": {
@@ -382,6 +406,11 @@ Refer to the HTTP header Accept-Language to understand how to format this value.
 
 Default viewport width when width is not specified in the rendering request. Default is `1000`.
 
+```bash
+# Available from v3.9.0+
+RENDERING_VIEWPORT_WIDTH=1000
+```
+
 ```json
 {
   "rendering": {
@@ -394,6 +423,11 @@ Default viewport width when width is not specified in the rendering request. Def
 
 Default viewport height when height is not specified in the rendering request. Default is `500`.
 
+```bash
+# Available from v3.9.0+
+RENDERING_VIEWPORT_HEIGHT=500
+```
+
 ```json
 {
   "rendering": {
@@ -406,6 +440,11 @@ Default viewport height when height is not specified in the rendering request. D
 
 Limit the maximum viewport width that can be requested. Default is `3000`.
 
+```bash
+# Available from v3.9.0+
+RENDERING_VIEWPORT_MAX_WIDTH=1000
+```
+
 ```json
 {
   "rendering": {
@@ -418,6 +457,11 @@ Limit the maximum viewport width that can be requested. Default is `3000`.
 
 Limit the maximum viewport height that can be requested. Default is `3000`.
 
+```bash
+# Available from v3.9.0+
+RENDERING_VIEWPORT_MAX_HEIGHT=500
+```
+
 ```json
 {
   "rendering": {
@@ -431,6 +475,11 @@ Limit the maximum viewport height that can be requested. Default is `3000`.
 Specify default device scale factor for rendering images. `2` is enough for monitor resolutions, `4` would be better for printed material. Setting a higher value affects performance and memory. Default is `1`.
 This can be overridden in the rendering request.
 
+```bash
+# Available from v3.9.0+
+RENDERING_VIEWPORT_DEVICE_SCALE_FACTOR=2
+```
+
 ```json
 {
   "rendering": {
@@ -443,6 +492,11 @@ This can be overridden in the rendering request.
 
 Limit the maximum device scale factor that can be requested. Default is `4`.
 
+```bash
+# Available from v3.9.0+
+RENDERING_VIEWPORT_MAX_DEVICE_SCALE_FACTOR=4
+```
+
 ```json
 {
   "rendering": {