Unfortunately, your image didn't seem to make it.
Fiddler uses as much memory as it needs to hold the traffic it displays; if you want Fiddler to lower its memory usage, you should remove Sessions from the Web Sessions list. One approach for doing so is to use the "Keep Only" option on Fiddler's toolbar to limit the number of Sessions kept.
See http://docs.telerik.com/fiddler/Troubleshoot-Fiddler/OutOfMemory for discussion.
Note that running the latest build of Fiddler (4.6) on the latest .NET Framework (v4.6) can decrease memory usage vs. running older versions.
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