Democratic presidential candidate Hillary Clinton's image has picked up among Democrats and Democratic-leaning independents over the last two weeks. Clinton now has a favorable rating of 73% and an unfavorable rating of 20%, yielding an overall net favorable score of +53. Her net favorable score had dropped to as low as +46 earlier in September.

One problem Clinton does not have is name identification. Her familiarity score has consistently been over 90% since Gallup began tracking in mid-July.

From a big-picture perspective, Clinton's image among Democrats clearly deteriorated as the campaign progressed during the summer and into September, in part as a result of the controversy over her emails while she was secretary of state. Her net favorable score had been as high as +62 in early August -- thus leading to a 16-point drop between that time and mid-September.

Now, as noted, her image has begun to improve. We rely on two-week rolling averages to provide large sample sizes and stable estimates when trending the candidates' images, but a look at just the last seven days through Sept. 27 shows that her net favorable image among Democrats is at +57, suggesting a clear upward trajectory.

Vermont Sen. Bernie Sanders' image among Democrats has plateaued well below Clinton's throughout September, after having edged upward from early August. Sanders' favorable rating is now 48% and his unfavorable is 12%, yielding his current +36 net favorable rating. Sanders has become more familiar to Democrats over the past two months, but four in 10 Democrats and leaners still don't know enough about him to have an opinion.

The next major event for Clinton and Sanders will be the first Democratic debate on Oct. 13. CNN will be televising the debate and announced a very inclusive policy for allowing candidates to participate, ensuring that announced candidates Martin O'Malley, Jim Webb and Lincoln Chafee would be able to be on stage, along with Vice President Joe Biden, if he were to declare that he is running by Oct. 13.