diff --git a/.gitignore b/.gitignore
index e62264a..f1bf5b9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,6 +9,7 @@
 Package.resolved
 .swiftpm/
 Public/images/
+Public/thumbnails/
 Public/classifier.version
 Public/classifier.mlmodel
 Public/caps.json
diff --git a/Sources/App/CapServer.swift b/Sources/App/CapServer.swift
index eb66514..dd23006 100644
--- a/Sources/App/CapServer.swift
+++ b/Sources/App/CapServer.swift
@@ -8,6 +8,11 @@ final class CapServer: ServerOwner {
     
     private let imageFolder: URL
 
+    private let thumbnailFolder: URL
+    
+    /// The file where the cap count is stored for the grid webpage
+    private let gridCountFile: URL
+    
     /// The file where the database of caps is stored
     private let dbFile: URL
 
@@ -73,6 +78,8 @@ final class CapServer: ServerOwner {
 
     init(in folder: URL, writers: [String]) {
         self.imageFolder = folder.appendingPathComponent("images")
+        self.thumbnailFolder = folder.appendingPathComponent("thumbnails")
+        self.gridCountFile = folder.appendingPathComponent("count.js")
         self.dbFile = folder.appendingPathComponent("caps.json")
         self.htmlFile = folder.appendingPathComponent("count.html")
         self.classifierVersionFile = folder.appendingPathComponent("classifier.version")
@@ -217,6 +224,10 @@ final class CapServer: ServerOwner {
     func folder(of cap: Int) -> URL {
         imageFolder.appendingPathComponent(String(format: "%04d", cap))
     }
+    
+    func thumbnail(of cap: Int) -> URL {
+        thumbnailFolder.appendingPathComponent(String(format: "%04d.jpg", cap))
+    }
 
     func file(of cap: Int, version: Int) -> URL {
         folder(of: cap).appendingPathComponent(String(format: "%04d-%02d.jpg", cap, version))
@@ -384,6 +395,7 @@ final class CapServer: ServerOwner {
         cap.classifierVersion = nextClassifierVersion
         caps[cap.id] = cap
         saveCapCountHTML()
+        updateGridCapCount()
         log("Added cap \(cap.id) '\(cap.name)'")
     }
 
@@ -426,6 +438,29 @@ final class CapServer: ServerOwner {
         classifierVersion = version
         log("Updated classifier to version \(version)")
     }
+    
+    func getListOfMissingThumbnails() -> [Int] {
+        caps.keys.filter { !fm.fileExists(atPath: thumbnail(of: $0).path) }
+    }
+    
+    func saveThumbnail(_ data: Data, for cap: Int) {
+        let url = thumbnail(of: cap)
+        do {
+            try data.write(to: url)
+        } catch {
+            log("Failed to save thumbnail \(cap): \(error)")
+        }
+    }
+    
+    private func updateGridCapCount() {
+        do {
+            try "const numberOfCaps = \(capCount);"
+                .data(using: .utf8)!
+                .write(to: gridCountFile)
+        } catch {
+            log("Failed to save grid cap count: \(error)")
+        }
+    }
 
     // MARK: ServerOwner
 
diff --git a/Sources/App/routes.swift b/Sources/App/routes.swift
index d1b6950..207f9c3 100755
--- a/Sources/App/routes.swift
+++ b/Sources/App/routes.swift
@@ -29,11 +29,8 @@ func routes(_ app: Application) {
     // Add or change a cap
     app.postCatching("cap") { request in
         try authorize(request)
-        guard let buffer = request.body.data else {
-            log("Invalid body data")
-            throw CapError.invalidBody
-        }
-        let cap = try decoder.decode(Cap.self, from: buffer)
+        let data = try request.getBodyData()
+        let cap = try decoder.decode(Cap.self, from: data)
         try server.addOrUpdate(cap)
     }
     
@@ -44,11 +41,7 @@ func routes(_ app: Application) {
             log("Invalid parameter for cap")
             throw Abort(.badRequest)
         }
-        guard let buffer = request.body.data else {
-            log("Missing body data: \(request.body.description)")
-            throw CapError.invalidBody
-        }
-        let data = Data(buffer: buffer)
+        let data = try request.getBodyData()
         try server.save(image: data, for: cap)
     }
     
@@ -62,11 +55,7 @@ func routes(_ app: Application) {
         guard version > server.classifierVersion else {
             throw Abort(.alreadyReported) // 208
         }
-        guard let buffer = request.body.data else {
-            log("Missing body data: \(request.body.description)")
-            throw CapError.invalidBody
-        }
-        let data = Data(buffer: buffer)
+        let data = try request.getBodyData()
         try server.save(classifier: data, version: version)
         return .ok
     }
@@ -83,16 +72,44 @@ func routes(_ app: Application) {
         }
         
         try authorize(request)
-        guard let buffer = request.body.data else {
-            log("Missing body data: \(request.body.description)")
-            throw CapError.invalidBody
-        }
-        let data = Data(buffer: buffer)
-        guard let content = String(data: data, encoding: .utf8) else {
-            log("Invalid string body: \(request.body.description)")
-            throw CapError.invalidBody
-        }
-        server.updateTrainedClasses(content: content)
+        let body = try request.getStringBody()
+        
+        server.updateTrainedClasses(content: body)
         server.removeAllEntriesInImageChangeList(before: date)
     }
+    
+    // Get the list of missing thumbnails
+    app.get("thumbnails", "missing") { request in
+        let missingThumbnails = server.getListOfMissingThumbnails()
+        return missingThumbnails.map(String.init).joined(separator: ",")
+    }
+    
+    app.postCatching("thumbnails", ":cap") { request in
+        guard let cap = request.parameters.get("cap", as: Int.self) else {
+            log("Invalid cap parameter for thumbnail upload")
+            throw Abort(.badRequest)
+        }
+        let data = try request.getBodyData()
+        server.saveThumbnail(data, for: cap)
+    }
+}
+
+private extension Request {
+    
+    func getBodyData() throws -> Data {
+        guard let buffer = body.data else {
+            log("Missing body data")
+            throw CapError.invalidBody
+        }
+        return Data(buffer: buffer)
+    }
+    
+    func getStringBody() throws -> String {
+        let data = try getBodyData()
+        guard let content = String(data: data, encoding: .utf8) else {
+            log("Invalid string body")
+            throw CapError.invalidBody
+        }
+        return content
+    }
 }