diff --git a/src/endpoints/content-manager.js b/src/endpoints/content-manager.js
index 6cebf53b7..7102637f5 100644
--- a/src/endpoints/content-manager.js
+++ b/src/endpoints/content-manager.js
@@ -540,9 +540,21 @@ async function downloadGenericPng(url) {
 
         if (result.ok) {
             const buffer = Buffer.from(await result.arrayBuffer());
-            const fileName = sanitize(result.url.split('?')[0].split('/').reverse()[0]);
+            let fileName = sanitize(result.url.split('?')[0].split('/').reverse()[0]);
             const contentType = result.headers.get('content-type') || 'image/png'; //yoink it from AICC function lol
 
+            // The `importCharacter()` function detects the MIME (content-type) of the file
+            // using its file extension. The problem is that not all third-party APIs serve
+            // their cards with a `.png` extension. To support more third-party sites,
+            // dynamically append the `.png` extension to the filename if it doesn't
+            // already have a file extension.
+            if (contentType === 'image/png') {
+                const ext = fileName.match(/\.(\w+)$/); // Same regex used by `importCharacter()`
+                if (!ext) {
+                    fileName += '.png';
+                }
+            }
+
             return {
                 buffer: buffer,
                 fileName: fileName,
@@ -694,10 +706,12 @@ router.post('/importURL', async (request, response) => {
             type = 'character';
             result = await downloadRisuCharacter(uuid);
         } else if (isGeneric) {
-            console.info('Downloading from generic url.');
+            console.info('Downloading from generic url:', url);
             type = 'character';
             result = await downloadGenericPng(url);
         } else {
+            const receivedURL = new URL(url);
+            console.error(`Received an import for "${receivedURL.host}", but site is not whitelisted. This domain must be added to the config key "whitelistImportDomains" to allow import from this source.`);
             return response.sendStatus(404);
         }