I keep searching for it, but all I get are answers about changing the size on the store page and different views. What I want is to alter the size of cached thumbnail size that I get with
$product->getThumbnailUrl();
when I upload the new product and Magento creates the small image and thumbnail, not when I retrieve it.
Best Answer
By default magento not generate
small_image & thumbnail
on product save/create.It will create the small_image & thumbnail image only when you try to retrieve it.
If You want to change the resize the thumbnail image just pass the parameter with
$width & $height
in thegetThumbnailUrl
function.Refer this Mage_Catalog_Model_Product::getThumbnailUrl()
Now anwser for your question :
To create the thumbail/small image on product creation/save. We can use event observer
catalog_product_save_after
And in
Observer.php
we can force the system to create the thumbnail and small imageRefer this Link for event observer