Take a look at the response header to discover what might be causing issues with your static maps request.
When something goes wrong with the Google Static Maps API, you may encounter an error or warning message. Pay special attention to warnings if elements are missing from the map, and consider checking for warnings before deploying a new application. Keep in mind that these warnings may not be immediately visible because they are located in the HTTP header.
source: https://developers.google.com/maps/documentation/static-maps/intro#Moreinfo
The X-Staticmap-API-Warning header provides details about any errors or warnings encountered. There are specific limitations outlined in the documentation regarding geocoded locations or polyline vertices (15). This information can be found at
https://developers.google.com/maps/documentation/static-maps/error-messages#warnings
This knowledge could aid in troubleshooting your issue.
UPDATE
The URL for the Static Maps in your example is too lengthy, comprising 16187 symbols. The maximum URL length allowed by the Static Maps API is 8192 characters. The excess length results in an error
https://i.sstatic.net/5q9wc.png
If a long path is necessary, you should utilize encoded polyline calculation as described in
https://developers.google.com/maps/documentation/utilities/polylinealgorithm
and integrate it into your URL.
I have developed a simple JavaScript code that converts your coordinates into an encoded polyline. The result can be viewed at https://jsfiddle.net/xomena/tqv2zsq0/. The encoded polyline consists of 3064 characters, well within the permissible limit.
You can now incorporate this into your URL following the code snippet provided (run it to view the outcome)
<img src="https://maps.googleapis.com/maps/api/staticmap?size=250x200&path=color:0xff0000ff|weight:2|enc:i|kmGfit_LjpFhc_A`kJpg{AlkJpg..(truncated for brevity)..com/images/r-pin-icon.png
A warning message persists, which you can verify in the browser's network console as detailed earlier in my response.
https://i.sstatic.net/Q3XLC.png
The warning indicates
x-staticmap-api-warning: Failed to fetch image url http://192.168.1.194/public/images/g-pin-icon.png
Google cannot retrieve your custom icon due to its unavailability on public platforms–the address 192.168.1.194 belongs to your internal IP. To eliminate this warning, ensure your icons are published on publicly accessible hosts.