First option; Toggle different combinations of tiff, png & color format. If this does not improve the quality. See the following steps to install & use GhostScript Import.
*** Tips for losing details after plans are imported ***
To minimize the project file size, it defaults the image color format to monochrome (black & white). However, if you lose some details after converting images, such as textures of product or furniture, you can change the color format to grayscale to preserve the details. Tiff will pull in more details which will take longer to load. Grayscale it suggested for pulling in more detail.