Setting up a Child theme – functions.php

Adding to what Steven said, if there are theme functions that you wish to alter, first see if there is a filter or action hook you can use to alter behavior. If you do need to copy over a function’s declaration in order to change it, unless the function declaration is wrapped in if ( ! function_exists( 'function_name' )): logic (making it “pluggable”), you must give the function a new name and alter whatever code calls that function. You can only use the same name with pluggable functions, in which case your declaration should also use the if ( ! function_exists( 'function_name' )): logic or you’ll have trouble activating your child theme. Once activated, your version will take precedence.

Full text vs. excerpt behavior is one of the more confusing aspects of WP. There are a few options for you to choose from, but behavior is also influenced by your theme. If your theme forces full text and you don’t want to manually insert <!–more–> tags, adding a child theme with an edited index.php is a viable solution.

Such a simple thing, having one’s code actually work. Yet so rewarding when it does so after a struggle. Be careful, it can be addictive 🙂

Removal is a matter of editing the right template to remove the responsible code. Some CSS adjustment might be required if removal leaves a hole. But if you’ve correctly removed the image output code along with the related container HTML, the space ought to close up automatically.

It’s still a featured image even if it’s less featured and more thumbnail. Output the img tag anywhere you like with the_post_thumbnail('thumbnail'); (specify whatever size you like. I’d more likely use ‘medium’ over ‘thumbnail’) The call still needs to be within the loop context because the current post dictates what image is used. Outside of loop context, use get_the_post_thumbnail() which accepts a post argument. In this case you need to explicitly echo out the return, whereas the_post_thumbnail() echoes for you.

Sorry for the confusion. You place the call on the template where you want it to appear. Different themes can use different templates for the same purpose. content.php would be a likely candidate. If you have trouble identifying the right template, try the template debugger plugin.

“Loop context” is going to take some explaining. The templates involved for any given request will somewhere include code for “The Loop”, code which includes

while ( have_posts()) : the_post();
  //code to output a post
endwhile;

Calling the_post() establishes the current post in several global values, all within the scope of this loop. Outside of this loop, determining the current post from these global values is unreliable. the_post_thumbnail() gets the image related to the current post established by these global values, so you cannot reliably use it outside of the loop.

get_the_post_thumbnail() will also use the current post, but you can instead optionally specify a specific post. So if you’re outside the loop and can get the right post ID through your own means, this function can still be used.

So which function you use depends on whether it is used within or outside of the loop. Outside of the loop you need to tell it which post you want the image for. There is one exception. On singular pages where only one post had been queried for, the global values established in the loop will retain the current post values after the loop has completed. So for singular templates only, you can still use the_post_thumbnail() after the loop has completed.

I hope that makes more sense, though I fear I may have added more confusion instead of clarifying.