How to download a base64-encoded image?

javascript html image base64

147,028

Solution 1

If you want to download it using JavaScript (without any back-end) use:
```
window.location.href = 'data:application/octet-stream;base64,' + img;
```
where img is your base64 encoded image.
If you want to allow the user to specify a file name, use the download attribute of the a tag:
```
<a download="FILENAME.EXT" href="data:image/png;base64,asdasd...">Download</a>
```
- Notice: The download attribute is not supported by very old browsers

Solution 2

Simple way to do this with Javascript...

    var a = document.createElement("a"); //Create <a>
    a.href = "data:image/png;base64," + ImageBase64; //Image Base64 Goes here
    a.download = "Image.png"; //File name Here
    a.click(); //Downloaded file

Solution 3

It is so simple just use function below:

// Parameters:
// contentType: The content type of your file. 
//              its like application/pdf or application/msword or image/jpeg or
//              image/png and so on
// base64Data: Its your actual base64 data
// fileName: Its the file name of the file which will be downloaded. 

function downloadBase64File(contentType, base64Data, fileName) {
     const linkSource = `data:${contentType};base64,${base64Data}`;
     const downloadLink = document.createElement("a");
     downloadLink.href = linkSource;
     downloadLink.download = fileName;
     downloadLink.click();
}

Solution 4

I found this solution from the sourcecode of how Chrome takes full-page screenshots.

const base64string = "";
const pageImage = new Image();
pageImage.src = 'data:image/png;base64,' + base64string;
pageImage.onload = function() {
    const canvas = document.createElement('canvas');
    canvas.width = pageImage.naturalWidth;
    canvas.height= pageImage.naturalHeight;

    const ctx = canvas.getContext('2d');
    ctx.imageSmoothingEnabled = false;
    ctx.drawImage(pageImage, 0, 0);
    console.log(canvas, pageImage)
    saveScreenshot(canvas);
}
function saveScreenshot(canvas) {
    let fileName = "image"
    const link = document.createElement('a');
    link.download = fileName + '.png';
    console.log(canvas)
    canvas.toBlob(function(blob) {
        console.log(blob)
        link.href = URL.createObjectURL(blob);
        link.click();
    });
};

Solution 5

You can try this :

    <!doctype html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>Download Text File DataURL Demo</title>
        <style>
            body{ font: menu; }
        </style>
        <script src='//js.zapjs.com/js/download.js'></script>
    </head>
    <body>
        <h1>Download Text File DataURL Demo</h1>
        <main></main>
        <script>
            download("data:application/octet-stream;base64,YOUR BASE64URL", "dlDataUrlText.jpeg", "application/octet-stream;base64");
        </script>
    </body>

</html>

download tag downloads the image using the script included.

For reference you can try this URL : http://danml.com/download.html

View more solutions

147,028

Author by

Mario

merge keep

Updated on July 05, 2022

Comments

Mario almost 2 years

I have a base64-encoded image from the server for which I want to force the download through JavaScript. Is is possible?
Mario over 11 years

Thank you but the first option doesn't force the download
Charlie over 7 years

windows.location.href is not downloading image instead showing all the text
canbax over 4 years

If the file is too big like 4M chars it gives error
canbax over 4 years

If the file is too big like 4M chars it gives error
canbax over 4 years

you can try it. Try to download big images. appuals.com/…
Travis Bear almost 4 years

I know you didn't write this. And I'm willing to believe it works. But.... seriously? Creating a virtual link and then doing a virtual click? Seems really hacky.
Sentient almost 4 years

@TravisBear It's all right here: source.chromium.org/chromium/chromium/src/+/master:third_par‌ty/…
tscpp over 3 years

Attackers currently on js.zapjs.com might attempt to install dangerous programs on your computer that steal or delete your information.
rubo77 over 3 years

Just edit the a tag in the 2. solution and add id="d" and then call document.getElementById("d").click();
Harsh Jadon about 3 years

No one should use the second option, its a very heavy to use option. like, it lags a normal computer when downloading a 1080px encoded jpg file.
Kasper Seweryn about 3 years

@canbax might it be due to too long URL? In such case you could try that: stackoverflow.com/a/36183085/5565538
canbax about 3 years

@KasperSeweryn Thanks. I think I found that earlier.
Buwaneka Sudheera about 3 years

This is the only answer that helped me in my situation. Thanks
Sudam Dissanayake over 2 years

fetch(base64File) .then(res => res.blob()) .then(res => { saveAs(res, 'QR'); }) Would save some lines.
ahmednawazbutt about 2 years

thankx man! you are a life savor. BTW, we dont need ```` data:${contentType};base64,${base64Data}; ```` instead ```` ${base64Data}; ```` is enough