diff --git a/Sources/App/CapServer+Routes.swift b/Sources/App/CapServer+Routes.swift
index 96d4249..c035ea8 100755
--- a/Sources/App/CapServer+Routes.swift
+++ b/Sources/App/CapServer+Routes.swift
@@ -35,10 +35,10 @@ extension CapServer {
         }
 
         // Upload an image
-        app.postCatching("images", ":cap") { request in
+        app.postCatching("images", .parameter("cap")) { request in
             try self.ensureOperability()
             try authenticator.authorize(request)
-            guard let cap = request.parameters.get("n", as: Int.self) else {
+            guard let cap = request.parameters.get("cap", as: Int.self) else {
                 log("/images/:cap: Invalid 'cap' parameter")
                 throw Abort(.badRequest)
             }
diff --git a/Sources/App/CapServer.swift b/Sources/App/CapServer.swift
index 23adb66..23e6307 100644
--- a/Sources/App/CapServer.swift
+++ b/Sources/App/CapServer.swift
@@ -149,6 +149,10 @@ final class CapServer {
     }
 
     private func loadCaps() throws {
+        guard exists(dbFile) else {
+            log("No cap database found")
+            return
+        }
         do {
             let data = try Data(contentsOf: dbFile)
             caps = try JSONDecoder().decode([Cap].self, from: data)
@@ -340,9 +344,18 @@ final class CapServer {
         guard !unwrittenImageChanges.isEmpty else {
             return
         }
+
+        try ensureExistenceOfChangedImagesFile()
         
-        let handle = try FileHandle(forWritingTo: changedImagesFile)
-        try handle.seekToEnd()
+        let handle: FileHandle
+        do {
+            handle = try FileHandle(forWritingTo: changedImagesFile)
+            try handle.seekToEnd()
+        } catch {
+            log("Failed to open changed images file for writing: \(error)")
+            throw error
+        }
+
         var entries = unwrittenImageChanges
         defer {
             unwrittenImageChanges = entries
@@ -351,7 +364,12 @@ final class CapServer {
         let dateString = changedImageEntryDateFormatter.string(from: Date())
         while let entry = entries.popLast() {
             let content = "\(dateString):\(entry.cap):\(entry.image)\n".data(using: .utf8)!
-            try handle.write(contentsOf: content)
+            do {
+                try handle.write(contentsOf: content)
+            } catch {
+                log("Failed to write entry to changed images file: \(error)")
+                throw error
+            }
         }
     }
     
@@ -377,6 +395,10 @@ final class CapServer {
     }
     
     func removeAllEntriesInImageChangeList(before date: Date) {
+        guard exists(changedImagesFile) else {
+            log("No file for changed images to update")
+            return
+        }
         do {
             try String(contentsOf: changedImagesFile)
                 .components(separatedBy: "\n")
@@ -418,6 +440,7 @@ final class CapServer {
 
     private func add(_ cap: Cap) throws {
         guard cap.mainImage == 0 else {
+            log("Attempting to add cap \(cap.id) with main image \(cap.mainImage)")
             throw CapError.invalidData
         }
         var cap = cap
@@ -447,10 +470,12 @@ final class CapServer {
     
     func deleteImage(version: Int, for capId: Int) -> Bool {
         guard let cap = caps[capId] else {
+            log("Attempting to delete image \(version) of unknown cap \(capId)")
             return false
         }
         let capImageUrl = imageUrl(of: capId, version: version)
         guard exists(capImageUrl) else {
+            log("Attempting to delete missing image \(version) of cap \(capId)")
             return false
         }
         organizeImages(for: cap)
@@ -476,7 +501,7 @@ final class CapServer {
         do {
             try classifier.write(to: classifierFile)
         } catch {
-            log("Failed to write classifier: \(error)")
+            log("Failed to write classifier \(version): \(error)")
             throw Abort(.internalServerError)
         }
         classifierVersion = version