These would be in the apm_full.css stylesheet. I had luck adding the two commands below into the section for the image. You can use the Chrome developer tools to help locate the position in the CSS better.
Search for the section named tablemain_table tdmain_table_image_cell img.
Under this section add these two lines. This will place the image 270 pixels from the left side of the screen. You can specify the size of the forms page to 270 pixels in the layout settings. This is found under the common section in the advanced customization properties. This will make the image start right at the same pixel that the forms page ends at.
position: absolute;
left: 270px;