Hi v-bofeng,
Yes i have all the images converted to base64 and have checked numerous times on the compose, even side by side with the ones that do return the data. No errors in the flow, numerous efforts to resolve this with same results. In the end, modified flow to initalize variable (Name: objectList, Type: Object, Value: Body), then a Compose with html script in expression.
<td>',variables('objectList')?['WorkDetails'],'</td> returns all the data. In regards to images, this worked for me
<td><img src="',variables('objectList')?['Signature1'],'" width="60" height="60"></p>
Cheers,
Matt383