how to output all images in an entry's loop Unfortunately I'm still very new to Craft, but I have a question to which I haven't found an answer here or in the Docs or the ones I found don't seem to work in my case. 

I want to output all the images for each entry in this loop and I don't understand how I get the "set image = entry.startbilder" to work that way?

I understand that ".one()" only outputs the first image but how do I change that to output all images? changing that to ".all()" results in an error.

{% for entry in craft.entries.section('projekte').all() %}  
    &lt;a href="{{ entry.url }}"&gt;      
        {% set image = entry.startbilder.one() %}
        {% if image %}
            &lt;img src="{{ image.getUrl('medium') }}" alt="{{ image.title }}" /&gt;
        {% endif %}
    &lt;/a&gt;        
{% endfor %}


thanks in advance for any help!
You should use .all(), but that will give you an array of Assets. You can't call .getUrl() on an array, so you'd have to loop that array:

{% for entry in craft.entries.section('projekte').all() %}  
    &lt;a href="{{ entry.url }}"&gt;      
        {% set images = entry.startbilder.all() %}

        {% if images |length %}
            {% for image in images %}
                &lt;img src="{{ image.getUrl('medium') }}" alt="{{ image.title }}" /&gt;
            {% endfor %}
        {% endif %}
    &lt;/a&gt;        
{% endfor %}


If you'd want to eager load the images, this is how you'd do it:

{% for entry in craft.entries.section('projekte').with(['startbilder']).all() %}  
    &lt;a href="{{ entry.url }}"&gt;      
        {% if entry.startbilder |length %}
            {% for image in entry.startbilder %}
                &lt;img src="{{ image.getUrl('medium') }}" alt="{{ image.title }}" /&gt;
            {% endfor %}
        {% endif %}
    &lt;/a&gt;        
{% endfor %}