Filename Controls

If you’ve ever converted 50 images and then spent 10 minutes renaming them back to what they were, this update is for you.

Keep original filename

By default, imgfast renames your output files with quality and size info: photo-imgfast.com-q80-1200x800.webp. That’s useful when you’re comparing different quality settings side by side.

But sometimes you just want photo.webp. Especially when optimizing an entire archive of assets - you want to drop the optimized files right back into your project without renaming anything.

New checkbox in Conversion Options: Keep original filename. Check it, and your downloads keep the original name with the new extension. That’s it. Works for single files, batch uploads, and archive processing.

The live preview below the checkbox shows exactly what your output filename will look like, updating as you change format, quality, and dimensions. No guessing.

Name normalization (Pro)

This one’s for developers and anyone who’s received a ZIP of Product placeholder (important!) FINAL.jpg from a designer.

Three dropdowns in Advanced Options let you clean up filenames on the fly:

Case - Force lowercase, UPPERCASE, Sentence case, or Title Case. That inconsistent mix of Hero_Banner.jpg and footer-logo.PNG becomes uniform in one batch.

Separator - Replace spaces, underscores, dashes, and dots with your preferred separator. My Cool Photo becomes my-cool-photo or my_cool_photo.

Non-ASCII - Handle international characters:

• Normalize strips diacritics: café becomes cafe
• Transliterate converts scripts: Cyrillic, Arabic, Hebrew, Greek, Japanese kana all become Latin equivalents
• Remove just drops non-ASCII characters entirely

Strip special characters - A checkbox that removes brackets, parentheses, punctuation, and other non-alphanumeric junk. Product (important!) [v2] {final}.jpg becomes Product important v2 final.jpg. Combine with a separator option and you get product-important-v2-final.jpg.

These compose naturally. The preview updates live so you see exactly what you’ll get.

The transliteration covers Cyrillic, Arabic, Hebrew, Greek, Farsi, Japanese Hiragana/Katakana, and a bunch of Latin special characters that standard normalization misses (Polish, Turkish, Scandinavian, Icelandic). For scripts we don’t cover in the preview (Chinese, Korean, Thai), the actual download uses full Unicode transliteration server-side.

API support

Both features are available in the API:

curl -X POST https://imgfast.com/api/v1/convert \
  -H "X-API-Key: imgfast_your_api_key" \
  -F "file=@image.jpg" \
  -F "output_format=webp" \
  -F "preserve_name=true" \
  -F "name_case=lowercase" \
  -F "name_separator=dash" \
  -F "name_ascii=transliterate" \
  -F "name_strip_special=true"

Bug fix: non-ASCII filenames

We also fixed a pre-existing bug where downloading any file with non-ASCII characters in the original filename (Cyrillic, Arabic, etc.) would crash with a server error. The Content-Disposition HTTP header only accepts ASCII, and we weren’t encoding it properly. Now all filenames are RFC 5987 encoded - browsers see the full Unicode name, and the server doesn’t choke on it. This fix applies to all download endpoints, not just the converter.