You can use images from the Document Space (more about Document Space) in your Templates.
You can add it as placeholders in blocks ‘Document info’ and ‘Placeholder’:

When you are editing it, click on ‘Placeholder’ -> ‘Document space images’ -> choose the image -> save changes:

So this image will be displayed in your template as below:

‘No image available’ on Invoices

If there is a “no image available” message on Invoice preview or on Print Invoice…

… it’s probably because this template was using an image uploaded to the document space.
So when you deleted this image from the zistemo storage space, on the Invoices/Estimates and anywhere it was used – the message ‘No image available’ will show up instead.

If you want to remove this message from the invoice, you can:
1) choose another template
2) delete this image from the template used for this invoice (on Template editor) -> then go to the invoice page and refresh the page.