Upload an image to a Google spreadsheet

Question

I am making a photo shooting contest, the competitor should register using a Google registration form, and upload his photo as well. I searched all over the internet to find

Answer 1

EDIT : I upgrade change the code a little bit, because as yyk mentionned, UiApp "doclist" deprecated since December 11, 2014. I use it to create a trombinoscope (i don't know the word in english, group gallery perhaps) in a google doc, people uploaded their picture nd name in a form. I don't use a spreadsheet. Here is the code :

   function doGet(e) {
var app = UiApp.createApplication().setTitle('Trombi');
var panel = app.createFormPanel();
var grid = app.createGrid(3,2).setId('registrationGrid');
var nameLabel = app.createLabel('Name');
var nameTextbox = app.createTextBox().setWidth('150px').setName('Name');
var submitButton = app.createSubmitButton('send'); 
var warning = app.createHTML('Please wait').setStyleAttribute('background','yellow').setVisible(false)
//file upload
var upLoadTypeLabel = app.createLabel('File to Upload');
var upLoad = (app.createFileUpload().setName('thefile'));
//Grid layout of items on form
grid.setWidget(0, 0, nameLabel)
    .setWidget(0, 1, nameTextbox)
    .setWidget(1, 0, upLoadTypeLabel)
    .setWidget(1, 1, upLoad)
    .setWidget(2, 0, submitButton)
    .setWidget(2, 1, warning)
var cliHandler = app.createClientHandler().forTargets(warning).setVisible(true)
submitButton.addClickHandler(cliHandler);  
panel.add(grid);
app.add(panel);
return app;}

function doPost(e) {
var app = UiApp.getActiveApplication();  
var Name = e.parameter.Name;
//app.getElementById('info').setVisible(true).setStyleAttribute('color','red');
 // data returned is a blob for FileUpload widget
var fileBlob = e.parameter.thefile;  
var doc = DriveApp.createFile(fileBlob).setName(Name); 
var doc = DocumentApp.openById('your key');
var body = doc.getBody();
var inlineI = body.appendImage(fileBlob);
  var width = inlineI.getWidth();
  var newW = width;
  var height = inlineI.getHeight();
  var newH = height;
  var ratio = width/height;
  Logger.log('w='+width+'h='+height+' ratio='+ratio);
  if(width>200){
  newW = 200;
  newH = parseInt(newW/ratio);
  }
  inlineI.setWidth(newW).setHeight(newH)
  body.appendParagraph(Name);
  body.appendHorizontalRule();
doc.saveAndClose();
app.add(app.createLabel('success')); 
return app
 }