Dear Andreas,
as shown in the screenshot attached the values in the select of Scharfe field is pure text – I do not see <img> tag or img src http address.
The icons displayed are probaly cached, I changed the value of 28th from 'Keine Chilli' which has an empty value, to '2 Chilli – Scharf' and it correctly diaplays 'Scharfe'.
If you want to use this fields as you try to do, I suggest you again to place the http address of the images as the value in the fiedls and then use it as such:
<h5 class="speise-titel"> [wpv-post-title] <span><img src="types field="schaerfe"][/types]" alt="" /></span> </h5>
Then fix the spaces and such accordingly to what Views prefer in order to render what you want to.
Please let me know if there is anything else I can assist you with.