In Invoicing Settings Invoice Groups, while adding a new group (+ Add new group), or editing an existing one 
:
Settings
Logo
| Logo | Company logo which will be used for all invoices of the invoice group. Upload logo picture in PNG format, 24 bit, no transparency. Maximum picture size is 1 MB. |
|---|---|
| Logo - width | Adjust logo width in a graphical editor and set size in millimetres. |
| Logo - left margin | Distance of logo from left margin (A4) in mm; it is used for logo shift on printed invoices. Measure the real position on printed invoice with a ruler. If you fill in values with 0 the picture will not be shown on next printing of invoices. |
| Logo - top margin | Distance of logo from top margin (A4) in mm; it is used for logo shift on printed invoices. Measure the real position on printed invoice with a ruler. If you fill in values with 0 the picture will not be shown at next printing of invoices. |
Stamp
| Stamp | The same as for logo settings applies. |
|---|---|
| Position of the stamp on the invoice with postal order | Settings for placement of logo on invoices with postal money order in the bottom. |
| Stamp - cash payment | Stamp displayed on cash receipt; recommended settings: |
| Stamp - cash payment - width | 50 mm (Stamp width) |
| Stamp - cash payment - left margin | 130 mm (Left margin) |
| Stamp - cash payment - top margin | 115 mm (Top margin) |
The easiest way to convert stamp or logo picture is to paste it to MS Windows Painting application. Then you select a requested PNG format, and save the picture.
This settings will be applied at next printing of invoices. Invoices issued prior to this change will remain unchanged.
Click on show to display picture preview, or 
Preview to display entire invoice.
Removal
If you fill in millimetre values (width, margins) with 0 the picture will not be shown at next printing of invoices.
This way you discontinue logo or stamp display for newly issued invoices. It is possible to correct issued invoices only by their cancelling and issuing new ones. Ultimate solution is to use database intervention of our technical support.