<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-04-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000025354</issuerCik>
        <issuerName>CPI CORP</issuerName>
        <issuerTradingSymbol>CPY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001285596</rptOwnerCik>
            <rptOwnerName>MITCHELL MARK R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>666 THIRD AVE 26TH FL</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>CPI Corp. Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-04-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>693</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5151</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <remarks>Award under Company's Restricted Stock Plan pursuant to Director's election to receive restricted stock in lieu of cash compensation for 2007 board retainer.  Shares granted vest in full on February 2, 2008.


Mark Mitchell is a portfolio manager of RCG Ambrose Master Fund, Ltd (&quot;Ambrose&quot;). As such Mr. Mitchell makes day to day investment decisions with respect to the securities held in Ambrose.  In addition, Mr. Mitchell trades on behalf of affiliates of Ambrose, including Starboard Value &amp; Opportunity Fund, LLC, Ramius Securities, LLC and Ramius Master Fund, Ltd. Currently, Ambrose, Ramius Securities, Ramius Master Fund, Ltd. and Starboard Value &amp; Opportunity Fund, LLC hold 882,000 shares of CPI Corp. in the aggregate. The Investment Advisor to Ambrose is Ramius Capital Group, LLC. Ramius Securities, LLC is an affiliate and wholly owned subsidiary of Ramius Capital Group, LLC. The Investment Advisor to Ramius Master Fund, Ltd. is Ramius Advisors, LLC, another affiliate and wholly owned subsidiary of Ramius Capital Group, LLC. The Managing Member of Ramius Capital Group, LLC is C4S &amp; Co., LLC. Mark Mitchell is a limited partner of C4S &amp; Co., LLC.  The Managing Member of Starboard Value &amp; Opportunity Fund, LLC is Admiral Advisors, LLC whose sole member is Ramius Capital Group, LLC. Mr. Mitchell does not have investment or voting control over shares held by any of Ambrose, Ramius Securities, Ramius Master Fund or Starboard Value &amp; Opportunity Fund, LLC.</remarks>

    <ownerSignature>
        <signatureName>Mark R. Mitchell</signatureName>
        <signatureDate>2007-04-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
