diff --git a/apps/api/src/http/upload/index.ts b/apps/api/src/http/upload/index.ts
index a66bec1..765840c 100644
--- a/apps/api/src/http/upload/index.ts
+++ b/apps/api/src/http/upload/index.ts
@@ -67,7 +67,7 @@ function readImageDimensions(file: Express.Multer.File): { width: number; height
     let offset = 2
     while (offset + 9 < buffer.length) {
       if (buffer[offset] !== 0xff) return null
-      const marker = buffer[offset + 1]
+      const marker = buffer.readUInt8(offset + 1)
       const length = buffer.readUInt16BE(offset + 2)
       if (length < 2) return null
       if ((marker >= 0xc0 && marker <= 0xc3) || (marker >= 0xc5 && marker <= 0xc7) || (marker >= 0xc9 && marker <= 0xcb) || (marker >= 0xcd && marker <= 0xcf)) {