SCCM 2016 adds boot images automatically during automatically which are based on Windows PE version from the supported version of Windows AIK or Windows ADK. Depending upon the version of SCCM, you might be able to add boot images based on different version of Windows AIK.
Every version of Microsoft SCCM supports boot images from specific versions of the Windows Automated Installation Kit (AIK or ADK).
For Detailed information on Boot images, please visit here
You can also create custom boot images with tools that include extra components and features and import into SCCM. more information is available here
For SCCM 2016, make sure that boot images are configured for PXE support.
Launch Microsoft Configuration Manager Console
Go to Software Library > Operating Systems > Boot Images
Right Click on Boot Images (x64) and Click Properties
Go to Tab Data Source
Make sure that Deploy this boot image from the PXE-enabled distribution point is checked
Go to Tab Customization
Check Enable command support (testing only)
Enable command support (testing only), will allow to troubleshoot OS deployment issues.
This complete the Boot Images configuration!