diff --git a/dist/index.js b/dist/index.js
index 077ee59..2d70d72 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -3,6 +3,7 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
+exports.changeDpiBuffer = changeDpiBuffer;
 exports.changeDpiBlob = changeDpiBlob;
 exports.changeDpiDataUrl = changeDpiDataUrl;
 
@@ -51,6 +52,40 @@ var _H = 'H'.charCodeAt(0);
 var _Y = 'Y'.charCodeAt(0);
 var _S = 's'.charCodeAt(0);
 
+function isBufferPNG(buffer) {
+  if (buffer.length < 8) return;
+  return buffer[0] === 137 && buffer[1] === 80 && buffer[2] === 78 && buffer[3] === 71 && buffer[4] === 13 && buffer[5] === 10 && buffer[6] === 26 && buffer[7] === 10;
+}
+
+function isBufferJPEG(buffer) {
+  if (buffer.length < 3) return;
+  return buffer[0] === 255 && buffer[1] === 216 && buffer[2] === 255;
+}
+
+function getType(buffer) {
+  if (isBufferJPEG(buffer)) {
+    return JPEG;
+  }
+  if (isBufferPNG(buffer)) {
+    return PNG;
+  }
+}
+
+function mergedTypedArrays(a, b) {
+  var c = new a.constructor(a.length + b.length);
+  c.set(a);
+  c.set(b, a.length);
+  return c;
+}
+
+function changeDpiBuffer(buffer, dpi) {
+  var headerChunk = new Uint8Array(buffer.slice(0, 33));
+  var rest = buffer.slice(33);
+  var type = getType(buffer);
+  var changedHeader = changeDpiOnArray(headerChunk, dpi, type);
+  return mergedTypedArrays(changedHeader, rest);
+}
+
 function changeDpiBlob(blob, dpi) {
   // 33 bytes are ok for pngs and jpegs
   // to contain the information.
diff --git a/src/index.js b/src/index.js
index cc52a9c..4290d6a 100644
--- a/src/index.js
+++ b/src/index.js
@@ -41,6 +41,40 @@ const _H = 'H'.charCodeAt(0);
 const _Y = 'Y'.charCodeAt(0);
 const _S = 's'.charCodeAt(0);
 
+function isBufferPNG(buffer) {
+  if (buffer.length < 8) return;
+  return buffer[0] === 137 && buffer[1] === 80 && buffer[2] === 78 && buffer[3] === 71 && buffer[4] === 13 && buffer[5] === 10 && buffer[6] === 26 && buffer[7] === 10;
+}
+
+function isBufferJPEG(buffer) {
+  if (buffer.length < 3) return;
+  return buffer[0] === 255 && buffer[1] === 216 && buffer[2] === 255;
+}
+
+function getType(buffer) {
+  if (isBufferJPEG(buffer)) {
+    return JPEG;
+  }
+  if (isBufferPNG(buffer)) {
+    return PNG;
+  }
+}
+
+function mergedTypedArrays(a, b) {
+  var c = new a.constructor(a.length + b.length);
+  c.set(a);
+  c.set(b, a.length);
+  return c;
+}
+
+export function changeDpiBuffer(buffer, dpi) {
+  const headerChunk = new Uint8Array(buffer.slice(0, 33));
+  const rest = buffer.slice(33);
+  const type = getType(buffer);
+  const changedHeader = changeDpiOnArray(headerChunk, dpi, type);
+  return mergedTypedArrays(changedHeader, rest);
+}
+
 export function changeDpiBlob(blob, dpi) {
   // 33 bytes are ok for pngs and jpegs
   // to contain the information.
diff --git a/test/test.spec.js b/test/test.spec.js
index f75252b..1a91744 100644
--- a/test/test.spec.js
+++ b/test/test.spec.js
@@ -1,6 +1,6 @@
 import chai, { expect } from 'chai';
 import fs from 'fs';
-import { changeDpiDataUrl, changeDpiBlob } from '../src/index';
+import { changeDpiDataUrl, changeDpiBlob, changeDpiBuffer } from '../src/index';
 import btoa from 'btoa';
 import atob from 'atob';
 
@@ -58,6 +58,13 @@ describe('It can convert dpi', function() {
       expect(Buffer.compare(blob,b)).to.not.equal(0);
     });
   });
+  it("JPEG conversion buffer", function() {
+    const jpeg123 = fs.readFileSync(__dirname + '/jpeg123.jpg');
+    const jpeg456 = fs.readFileSync(__dirname + '/jpeg456.jpg');
+    const converted = changeDpiBuffer(jpeg123, 456, 'image/jpeg');
+    expect(Buffer.compare(converted,jpeg456)).to.equal(0);
+    expect(Buffer.compare(converted,jpeg123)).to.not.equal(0);
+  })
   // it('PNG conversion blob', function() {
   //   const b = fs.readFileSync(__dirname + '/test415.png');
   //   const a = fs.readFileSync(__dirname + '/test830.png');