I've been using Kus's answer found here:
However moving from my local to the testing server it looks like the class is not being read and I lose the button to upload.
This is my image block
<widgetpress_list type="springwidget_press/List" module="springwidget_press">
....
<image>
<label>Press Image</label>
<description>Image to be displayed on the page</description>
<visible>1</visible>
<type>label</type>
<helper_block>
<type>springwidget_press/imagechooser</type>
<data>
<button translate="open">
<open>Insert Image...</open>
</button>
</data>
</helper_block>
</image>
....
</widgetpress_list>
This is my class name in a file called app/code/local/Spring/Press/Block/ImageChooser.php
class Spring_Press_Block_ImageChooser extends Mage_Adminhtml_Block_Template
{
public function prepareElementHtml(Varien_Data_Form_Element_Abstract $element)
{
.
.
.
}
}
Any ideas?