Image to Base64 converts in both directions between an image file and its text encoding. Encoding: choose a picture and you get four outputs at once — the complete Data URL (data:image/png;base64,…, ready to drop into src or url()), the bare Base64 without the prefix, a background-image: url('…'); CSS snippet, and an <img src=… alt=filename /> HTML snippet. Each has its own copy button, and the card title shows the encoded size and how much it grew. Decoding: paste a Data URL or bare Base64 and the tool sniffs the header for PNG / JPEG / GIF / WebP / BMP / SVG, then previews and downloads the result. Everything happens locally in the browser.

The difference from the general-purpose “Base64 Encode / Decode” is that this one is image-aware: it adds the MIME prefix, produces CSS / HTML you can paste straight in, and turns text back into a picture you can look at.

1. 01Pick a directionswitch between “Image → Base64” and “Base64 → Image” at the top.
2. 02Encodeadd one or more images and click “View” in the file list to switch between them. In “Encoded output”, any of the four text boxes longer than 1,500 characters shows only the beginning plus the total length; the copy buttons always copy the full content.
3. 03Decodepaste a string beginning data:image/...;base64,, or bare Base64, into the “Paste Base64” box (whitespace and line breaks are stripped) and click “Decode preview”.
4. 04Savea successful decode shows the MIME type and size; click “Download image” and the file arrives with the matching extension, for example base64-image.png.

Base64 is about 1.33× the size of the original file

Without a prefix the format is read from the file header

A 12 KB PNG icon

Data URL about 16 KB (+33%); CSS snippet `background-image: url('data:image/png;base64,iVBOR…');`

Paste bare Base64 beginning with `iVBORw0KGgo`

Sniffed as image/png, preview shown, downloaded as `.png`

Paste a string cut in half

“Decode failed: not valid Base64 content, check that the string is complete”

Supported input

JPG / PNG / WebP / GIF / BMP / AVIF / HEIC / SVG; HEIC is converted to JPEG before encoding, so the result is not the original HEIC bytes

Large files

beyond 3 MB the tool warns that the string will be extremely long, and a browser text box gets visibly sluggish with strings in the tens of megabytes

Sniffing range

the decoder recognises PNG, JPEG, GIF, WebP, BMP and SVG; anything else is treated as PNG

SVG

encoded as data:image/svg+xml;base64,…; the URL-encoded inline form is not produced

What it does not do

no compression or format change (use “Image Compress” or “Image Converter” first), and no Base64 for non-image files (use “Base64 Encode / Decode”)

Encoding and decoding run inside your browser through FileReader and atob; neither the image nor the Base64 text is uploaded to any server.