[docs] Mention Firefox's privacy.resistFingerprinting issue (#2190)

docs/docs/photos/troubleshooting/files-not-uploading.md

@@ -8,10 +8,18 @@ description:
 
 ## Network Issue
 
-If you are using VPN, please try disabling the VPN or switching provider.
+If you are using VPN, please try disabling the VPN or switching your provider.
 
 ## Web / Desktop
 
+### Disable "Faster uploads"
+
+We use a Cloudflare proxy to speed up uploads
+([blog post](https://ente.io/blog/tech/making-uploads-faster/)). However, in
+some network configurations (depending on the ISP) this might prevent uploads
+from going through, so if you're having trouble with uploads please try after
+disabling the "Faster uploads" setting in _Preferences > Advanced_.
+
 ### Certain file types are not uploading
 
 The desktop/web app tries to detect if a particular file is video or image. If

docs/docs/photos/troubleshooting/thumbnails.md

@@ -0,0 +1,16 @@
+---
+title: Missing thumbnails
+description:
+    Troubleshooting when thumbnails are not being generated when uploading
+    images in Ente Photos
+---
+
+# Missing thumbnails
+
+## Black thumbnails
+
+Users have reported an issue with Firefox which prevents the app from generating
+thumbnails if the "block canvas fingerprinting" setting in Firefox is enabled
+(i.e. `privacy.resistFingerprinting` is set to true in `about:config`). That
+feature blocks access to the canvas, and the app needs the canvas to generate
+thumbnails.