Create the url Field (Photo__c ) on Account object .

Please study below code , you will get the idea how to Achieve your requirement  

public with sharing class mycontact{
    //Variable Declaration
    private final contact con;
    public string Conlastname{get;set;}
    public string conphone{get;set;}
    public string conemail{get;set;}
    public string Conmobilephone{get;set;}
    public string Accid='';
    public blob Photo{get;set;}
    public string photoname{get;set;}
    public string photourl{get;set;}
    //Contstructor 
    public mycontact(apexpages.standardController controller){
        con=(Contact)controller.getRecord();
    }
    
    //this method updates the Contact with photourl and insert The Attachment Record
    public void UploadPhoto(){
        try{
            con.lastname = conlastname;  
            con.email = conemail;
            con.phone = conphone;
            con.mobilephone = conmobilephone;
            insert con;
           // Accid = ApexPages.currentPage().getParameters().get('id');  
           // inserting attachement with Attached photo      
            Attachment objA=new Attachment();
            objA.body = photo;
            objA.name = 'testname';
            objA.parentid= con.id;
            objA.ContentType = 'application/jpg';
            insert objA;
            string Attid= objA.id;
            string attachmentid=Attid.substring(0,15);
            con.imageUrl__c = '/servlet/servlet.FileDownload?file='+attachmentid;
            update con;
            photourl = con.imageurl__c;        
        }catch(Exception e){
            system.debug('Exception message'+e);
        }
     } 
}

<apex:page standardController="contact" sidebar="false" extensions="myAccount">    
    <style type="text/css">
       .img{width:100px !important;} 
       .bPageBlock .detailList tr td, .bPageBlock .detailList tr th, .hoverDetail .bPageBlock .detailList tr td, .hoverDetail .bPageBlock .detailList tr th { border-bottom: none !important;}
       .OptPanel{width:50%;float:left;padding-top:20px;borde:none !important; }   
       .Optpanel1{float:right;padding-right:100px;}   
       .bPageBlock, .individualPalette .bPageBlock
       {
            border: none !important;
           background:none !important;
       }
   
    </style>
    <apex:form >
         <fieldset>
            <legend>Update Your Contact Info</legend>
                <apex:outputpanel layout="block" styleclass="OptPanel">
                    <apex:pageblock mode="maindetail" >
                        <apex:pageblockSection columns="1">
                            <apex:pageblockSectionItem >
                                <apex:outputLabel value="Contact Name" />
                                <apex:inputtext value="{!conlastname}" />
                            </apex:pageblockSectionItem>
                            <apex:pageblockSectionItem >
                                <apex:outputLabel value="Phone" />
                                <apex:inputtext value="{!conphone}"/>
                            </apex:pageblockSectionItem>
                            <apex:pageblockSectionItem >
                                <apex:outputLabel value="Email" />
                                <apex:inputtext value="{!conemail}" /> 
                            </apex:pageblockSectionItem>
                            <apex:pageblockSectionItem >
                                <apex:outputLabel value="Mobile" />
                               <apex:inputtext value="{!conMobilePhone}" /> 
                            </apex:pageblockSectionItem>
                        </apex:pageblockSection>
                    </apex:pageblock>
               </apex:outputpanel>
                <apex:outputpanel layout="block" styleclass="Optpanel1">
                    <apex:pageblock mode="maindetail" >           
                        <apex:pageblocksection columns="1" >
                              <apex:image value="{!photourl}" url="{!photourl}"  rendered="{!if((photourl == ''),false,true)}" styleclass="img">   </apex:image>
                              <apex:image rendered="{!if((photourl == ''),true,false)}" url="https://c.cs12.content.force.com/profilephoto/005/F" styleclass="img" / >                  
                              <apex:inputFile value="{!photo}"> </apex:inputFile> 
                              <apex:commandButton value="Upload photo" action="{!uploadphoto}" />                                    
                        </apex:pageblocksection>
                    </apex:pageblock>
                 </apex:outputpanel>
           </fieldset>
    </apex:form>
</apex:page>

if you want to show image in Vf page , you need to Create Attachment with currently attached file and prepare url  for it , and update your Account with url . and display it in your Vf page .

Regards,

V'Nath