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#include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>
const char* ssid = "..............";
const char* password = "................";
String form = "<form action='led'><input type='radio' name='state' value='1' checked>On<input type='radio' name='state' value='0'>Off<input type='submit' value='Submit'></form>";
String imagepage = "<img src='/led.png'>";
// This is a png file (led.png)
const char image[] = {
0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d, 0x49, 0x48, 0x44, 0x52,
0x00, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x10, 0x08, 0x02, 0x00, 0x00, 0x00, 0x90, 0x91, 0x68,
0x36, 0x00, 0x00, 0x00, 0x01, 0x73, 0x52, 0x47, 0x42, 0x00, 0xae, 0xce, 0x1c, 0xe9, 0x00, 0x00,
0x00, 0x04, 0x67, 0x41, 0x4d, 0x41, 0x00, 0x00, 0xb1, 0x8f, 0x0b, 0xfc, 0x61, 0x05, 0x00, 0x00,
0x00, 0x20, 0x63, 0x48, 0x52, 0x4d, 0x00, 0x00, 0x7a, 0x26, 0x00, 0x00, 0x80, 0x84, 0x00, 0x00,
0xfa, 0x00, 0x00, 0x00, 0x80, 0xe8, 0x00, 0x00, 0x75, 0x30, 0x00, 0x00, 0xea, 0x60, 0x00, 0x00,
0x3a, 0x98, 0x00, 0x00, 0x17, 0x70, 0x9c, 0xba, 0x51, 0x3c, 0x00, 0x00, 0x00, 0x18, 0x74, 0x45,
0x58, 0x74, 0x53, 0x6f, 0x66, 0x74, 0x77, 0x61, 0x72, 0x65, 0x00, 0x50, 0x61, 0x69, 0x6e, 0x74,
0x2e, 0x4e, 0x45, 0x54, 0x20, 0x76, 0x33, 0x2e, 0x33, 0x36, 0xa9, 0xe7, 0xe2, 0x25, 0x00, 0x00,
0x00, 0x57, 0x49, 0x44, 0x41, 0x54, 0x38, 0x4f, 0x95, 0x52, 0x5b, 0x0a, 0x00, 0x30, 0x08, 0x6a,
0xf7, 0x3f, 0xf4, 0x1e, 0x14, 0x4d, 0x6a, 0x30, 0x8d, 0x7d, 0x0d, 0x45, 0x2d, 0x87, 0xd9, 0x34,
0x71, 0x36, 0x41, 0x7a, 0x81, 0x76, 0x95, 0xc2, 0xec, 0x3f, 0xc7, 0x8e, 0x83, 0x72, 0x90, 0x43,
0x11, 0x10, 0xc4, 0x12, 0x50, 0xb6, 0xc7, 0xab, 0x96, 0xd0, 0xdb, 0x5b, 0x41, 0x5c, 0x6a, 0x0b,
0xfd, 0x57, 0x28, 0x5b, 0xc2, 0xfd, 0xb2, 0xa1, 0x33, 0x28, 0x45, 0xd0, 0xee, 0x20, 0x5c, 0x9a,
0xaf, 0x93, 0xd6, 0xbc, 0xdb, 0x25, 0x56, 0x61, 0x01, 0x17, 0x12, 0xae, 0x53, 0x3e, 0x66, 0x32,
0xba, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4e, 0x44, 0xae, 0x42, 0x60, 0x82
// HTTP server will listen at port 80
ESP8266WebServer server(80);
const int led = 13;
void handle_adc() {
float val = analogRead(0);
server.send(200, "text/plain", String(val));
void handle_led() {
// get the value of request argument "state" and convert it to an int
int state = server.arg("state").toInt();
digitalWrite(led, state);
server.send(200, "text/plain", String("LED is now ") + ((state)?"on":"off"));
void handle_image() {
server.send(200, "image/png", "");
WiFiClient client = server.client();
client.write(image, sizeof(image));
void handle_webpage_with_image() {
server.send(200, "text/html", imagepage);
void setup(void) {
pinMode(led, OUTPUT);
// Connect to WiFi network
WiFi.begin(ssid, password);
// Wait for connection
while (WiFi.status() != WL_CONNECTED) {
Serial.print("Connected to ");
Serial.print("IP address: ");
// Set up the endpoints for HTTP server
// Endpoints can be written as inline functions:
server.on("/", [](){
server.send(200, "text/html", form);
// And as regular external functions:
server.on("/adc", handle_adc);
server.on("/led", handle_led);
server.on("/led.png", handle_image);
server.on("/showled", handle_webpage_with_image);
// Start the server
Serial.println("HTTP server started");
void loop(void) {
// check for incomming client connections frequently in the main loop:
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void handle_image() {
server.send(200, "image/png", "");
WiFiClient client = server.client();
client.write(image, sizeof(image));

This part of code don't work!! Look here..
I'm on Version 1.6.4-673-g8cd3697

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I can confirm that this code doesnt work, I get the WiFi but when I connect to the webserver the connection is refused, no website is shown..

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thk4711 commented Aug 27, 2015

How did you convert the png file to code ?

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When you open a new window is not shown in what is now the state of the LED. How to display the LED status when opening a new window in the browser?

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Would appreciate some help getting the handle_image() function to work. (The /adc and / handlers work as intended.)

The link above doesn't help (someone suggests putting the server.send after the client.write, but that doesn't work either.)

In response to /led.png, Firefox gives "The image at blah blah cannot be displayed because it contains errors." Others on esp8266 noted the same error.

If the led.png is saved, it is empty.

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void handle_image() {
server.send_P(200, "image/png", image, sizeof(image));

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pdfelen commented Oct 27, 2016

You can download a conversion tool from this link:

I can confirm that 'server.send_P()' as suggested by dorin-sima works fine in edge (windows 10), firefox (windows 10, android), chrome (android)

Thanks for this post!

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server.send(200, "text/plain", "This is an index page.");
I don't know what is "200" mean
Please help me to understand

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200 is a http response code, here's more info:

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Solo funciona de esta manera:
void handle_image() {
WiFiClient client = server.client();
client.write(image, sizeof(image));
server.send(200, "image/png", "");
Este orden esta chekeado al 2018. Muchas Gracias

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void handle_image() {
server.send_P(200, "image/png", image, sizeof(image));

Great Dorin-Sima !
You fix it !
Thanks so much !

Tested on Geekcreit ESP8266, with board as Wemos D1 R1 (led pin is gpio4)

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