Hey there, I’ve dealt with similar head-scratching OpenCart image issues before—let’s walk through the most likely fixes based on what you’ve described:

Since your local images open fine, but the uploaded versions are both unviewable on the site and corrupted for your team when downloaded, the root cause is almost always related to the transfer process or server-side handling. Here’s what to check step by step:

• Fix FTP Transfer Mode
  FTP clients often default to ASCII mode for text files, but this corrupts binary files like images. Double-check your FTP client settings: ensure you’re using Binary mode for all image uploads. Most clients let you set this per file type or globally—force it for JPG/PNG/WebP files and re-upload the problematic images.
• Validate File Integrity
  Compare the file size of your local image with the one on the server. If they don’t match, the transfer was incomplete. For a more precise check, generate a checksum:
  • On Linux/macOS: Run md5sum local-image.jpg and md5sum server-image.jpg (via SSH) — if the hashes differ, the server file is corrupted.
  • On Windows: Use CertUtil -hashfile local-image.jpg MD5 and compare with the server file’s hash.
• Try OpenCart’s Native File Manager
  Skip FTP entirely and upload the images using OpenCart’s built-in File Manager (under System > File Manager). Sometimes FTP clients have hidden bugs or permission glitches that the native tool avoids. If this works, your FTP setup is the issue.
• Check Server-Side Restrictions
  Even with 644 permissions, some hosting providers use security modules (like ModSecurity) that block or modify images with unusual metadata. Reach out to your host to ask if the uploaded images are being flagged or altered server-side.
• Re-Save Images with Standard Settings
  If your local images have non-standard encoding or metadata (e.g., saved with a rare JPG profile), servers or image viewers might struggle to parse them. Re-save the images using a basic tool (GIMP, Paint, or even Preview on macOS) with default settings, then re-upload.
• Test with a Known-Good Image
  Copy one of the working images in the same folder, rename it to match a problematic image’s filename, and see if it loads. If it does, this confirms the issue is with the file itself, not the folder, URL, or permissions.

内容的提问来源于stack exchange，提问作者Limpuls