<apex:page controller=”Sample”>
    <apex:pageBlock >
        <apex:image value=”{!photoURL}”/>
    </apex:pageBlock>
</apex:page>


Apex Controller:


public class Sample {
    public String photoURL {get;set;}


    public sample() {
        photoURL = [SELECT Id, smallPhotoURL FROM User WHERE ID =: UserInfo.getUserId()].smallPhotoURL;
    }



}

Output:

Cheers!!!