Yealink SIP-T2 Series Provisioning Manual page 88

Yealink IP Phones Auto provisioning Guide
select the file format as A/mu-law wave.
The original picture format must be *.bmp or *.gif. We recommend placing all files and
the PictureExDemo application to the root directory of the PC.
1. Double click the PictureExDemo.exe.
2. Click Add button to open a *.bmp or *.gif file.
You can repeat the second step to add multiple original picture files.
3. Click the Convert button.
Then you can find the DOB logo files in the adv directory.
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